CHAPTER 1 REVIEW EXERCISES

CONCEPT CHECK EXERCISES

Determine each of the following as being either true or false. If it is false, explain why.

  1. The absolute value of any real number is positive.

  2. 16 − 4 ÷ 2 = 14

  3. For approximate numbers, 26.7 − 15 = 11.7.

  4. 2a3 = 8a3

  5. 0.237 = 2.37 × 10 − 1

  6.  −  − 4 = 2

  7. 4x − (2x + 3) = 2x + 3

  8. (x − 7)2 = 49 − 14x + x2

  9. 6x + 22 = 3x

  10. If 5x − 4 = 0 , x = 5/4

  11. If a − bc = d , c = (d − a) / b

  12. In setting up the solution to a word problem involving numbers of gears, it would be sufficient to “let x = the first gear.”

PRACTICE AND APPLICATIONS

In Exercises 1324, evaluate the given expressions.

  1.  − 2 + ( − 5) − 3

  2. 6 − 8 − ( − 4)

  3. ( − 5)(6)( − 4)( − 2)(3)

  4. ( − 9)( − 12)( − 4)24

  5.  − 5 − | 2( − 6)|  +  − 153

  6. 3 − 5|  − 3 − 2|  − |  − 4|  − 4

  7. 183 − 5 − ( − 4)2

  8.  − ( − 3)2 −  − 8( − 2) − |  − 4| 

  9. 16 − 64

  10.  − 81 + 144

  11. (7)2 − 38

  12.  − 416 + (6)2

In Exercises 2532, simplify the given expressions. Where appropriate, express results with positive exponents only.

  1. ( − 2rt2)2

  2. (3a0b − 2)3

  3.  − 3mn − 5t(8m − 3n4)

  4. 15p4q2r5pq5r

  5.  − 16N − 2(NT2) − 2N0T − 1

  6.  − 35x − 1y(x2y)5xy − 1

  7. 45

  8. 9 + 36

In Exercises 3336, for each number, (a) determine the number of significant digits and (b) round off each to two significant digits.

  1. 8000

  2. 21,490

  3. 9.050

  4. 0.7000

In Exercises 3740, evaluate the given expressions. All numbers are approximate.

  1. 37.3 − 16.92(1.067)2

  2. 8.896 × 10 − 12 − 3.5954 − 6.0449

  3. 0.1958 + 2.8443.142(65)2

  4. 10.03568 + 37 ,  46629.632

In Exercises 4146, make the indicated conversions.

  1. 875 Btu to joules

  2. 18.4 in. to meters

  3. 65 km/h to ft/s

  4. 12.25 g / L to lb / ft3

  5. 225 hp to joules per minute

  6. 89.7 lb / in.2 to N / cm2

In Exercises 4778, perform the indicated operations.

  1. a − 3ab − 2a + ab

  2. xy − y − 5y − 4xy

  3. 6LC − (3 − LC)

  4.  − (2x − b) − 3( − x − 5b)

  5. (2x − 1)(5 + x)

  6. (C − 4D)(D − 2C)

  7. (x + 8)2

  8. (2r − 9s)2

  9. 2h3k2 − 6h4k52h2k

  10. 4a2x3 − 8ax4 − 2ax2

  11. 4R − [ 2r − (3R − 4r)] 

  12.  − 3b − [ 3a − (a − 3b)]  + 4a

  13. 2xy − { 3z − [ 5xy − (7z − 6xy)] } 

  14. x2 + 3b + [ (b − y) − 3(2b − y + z)] 

  15. (2x + 1)(x2 − x − 3)

  16. (x − 3)(2x2 + 1 − 3x)

  17.  − 3y(x − 4y)2

  18.  − s(4s − 3t)2

  19. 3p[ (q − p) − 2p(1 − 3q)] 

  20. 3x[ 2y − r − 4(x − 2r)] 

  21. 12p3q2 − 4p4q + 6pq52p4q

  22. 27s3t2 − 18s4t + 9s2t − 9s2t

  23. (2x2 + 7x − 30) ÷ (x + 6)

  24. (4x2 − 41) ÷ (2x + 7)

  25. 3x3 − 7x2 + 11x − 33x − 1

  26. w3 + 7w − 4w2 − 12w − 3

  27. 4x4 + 10x3 + 18x − 1x + 3

  28. 8x3 − 14x + 32x + 3

  29.  − 3{ (r + s − t) − 2[ (3r − 2s) − (t − 2s)] } 

  30. (1 − 2x)(x − 3) − (x + 4)(4 − 3x)

  31. 2y3 − 7y + 9y2 + 52y − 1

  32. 6x2 + 5xy − 4y22x − y

In Exercises 7990, solve the given equations.

  1. 3x + 1 = x − 8

  2. 4y − 3 = 5y + 7

  3. 5x7 = 32

  4. 2(4 − N) − 3 = 54

  5.  − 6x + 5 =  − 3(x − 4)

  6.  − 2( − 4 − y) = 3y

  7. 2s + 4(3 − s) = 6

  8. 2| x|  − 1 = 3

  9. 3t − 2(7 − t) = 5(2t + 1)

  10.  − (8 − x) = x − 2(2 − x)

  11. 2.7 + 2.0(2.1x − 3.4) = 0.1

  12. 0.250(6.721 − 2.44x) = 2.08

In Exercises 91100, change numbers in ordinary notation to scientific notation or change numbers in scientific notation to ordinary notation. (See Appendix B for an explanation of the symbols that are used.)

  1. A certain computer has 60,000,000,000,000 bytes of memory.

  2. The escape velocity (the velocity required to leave the Earth’s gravitational field) is about 25,000 mi/h.

  3. In 2015, the most distant known object in the solar system, a dwarf planet named V774104, was discovered. It was 15,400,000,000 km from the sun.

  4. Police radar has a frequency of 1.02 × 109 Hz . 

  5. Among the stars nearest the Earth, Centaurus A is about 2.53 × 1013 mi away.

  6. Before its destruction in 2001, the World Trade Center had nearly 107ft2 of office space.

  7. The faintest sound that can be heard has an intensity of about 10 − 12 W / m2 . 

  8. An optical coating on glass to reduce reflections is about 0.00000015 m thick.

  9. The maximum safe level of radiation in the air of a home due to radon gas is 1.5 × 10 − 1 Bq / L .  (Bq is the symbol for bequerel, the metric unit of radioactivity, where 1 Bq = 1 decay / s . )

  10. A certain virus was measured to have a diameter of about 0.00000018 m.

In Exercises 101114, solve for the indicated letter. Where noted, the given formula arises in the technical or scientific area of study.

  1. V = πr2L ,  for L (oil pipeline volume)

  2. R = 2GMc2 ,  for G (astronomy: black holes)

  3. P = π2EIL2 ,  for E (mechanics)

  4. f = p(c − 1) − c(p − 1) ,  for p (thermodynamics)

  5. Pp + Qq = Rr ,  for q (moments of forces)

  6. V = IR + Ir ,  for R (electricity)

  7. d = (n − 1)A ,  for n (optics)

  8. mu = (m + M)v ,  for M (physics: momentum)

  9. N1 = T(N2 − N3) + N3 ,  for N2 (mechanics: gears)

  10. Q = kAt(T2 − T1)L ,  for T1 (solar heating)

  11. R = A(T2 − T1)H ,  for T2 (thermal resistance)

  12. Z2(1 − λ2a) = k ,  for λ (radar design)

  13. d = kx2[ 3(a + b) − x]  ,  for a (mechanics: beams)

  14. V = V0[ 1 + 3a(T2 − T1)]  ,  for T2 (thermal expansion)

In Exercises 115120, perform the indicated calculations.

  1. A computer’s memory is 5.25 × 1013 bytes ,  and that of a model 30 years older is 6.4 × 104 bytes .  What is the ratio of the newer computer’s memory to the older computer’s memory?

  2. The time (in s) for an object to fall h feet is given by the expression 0.25h .  How long does it take a person to fall 66 ft from a sixth-floor window into a net while escaping a fire?

  3. The CN Tower in Toronto is 0.553 km high. The Willis Tower (formerly the Sears Tower) in Chicago is 442 m high. How much higher is the CN Tower than the Willis Tower?

  4. The time (in s) it takes a computer to check n cells is found by evaluating (n / 2650)2 .  Find the time to check 4.8 × 103 cells.

  5. The combined electric resistance of two parallel resistors is found by evaluating the expression R1R2R1 + R2 .  Evaluate this for R1 = 0.0275 Ω  and R2 = 0.0590 Ω .

  6. The distance (in m) from the Earth for which the gravitational force of the Earth on a spacecraft equals the gravitational force of the sun on it is found by evaluating 1.5 × 1011m / M ,  where m and M are the masses of the Earth and sun, respectively. Find this distance for m = 5.98 × 1024 kg and M = 1.99 × 1030 kg . 

In Exercises 121124, simplify the given expressions.

  1. One transmitter antenna is (x − 2a)ft long, and another is (x + 2a) yd long. What is the sum, in feet, of their lengths?

  2. In finding the value of an annuity, the expression (Ai − R)(1 + i)2 is used. Multiply out this expression.

  3. A computer analysis of the velocity of a link in an industrial robot leads to the expression 4(t + h) − 2(t + h)2 .  Simplify this expression.

  4. When analyzing the motion of a communications satellite, the expression k2r − 2h2k + h2rv2k2r is used. Perform the indicated division.

In Exercises 125136, solve the given problems.

  1. Does the value of 3 × 18 ÷ (9 − 6) change if the parentheses are removed?

  2. Does the value of (3 × 18) ÷ 9 − 6 change if the parentheses are removed?

  3.  In solving the equation x − (3 − x) = 2x − 3 ,  what conclusion can be made?

  4.  In solving the equation 7 − (2 − x) = x + 2 ,  what conclusion can be made?

  5. For x = 2 and y =  − 4 ,  evaluate (a) 2| x|  − 2| y|  ;  (b) 2| x − y|  . 

  6. If a < 0 ,  write the value of  | a |  without the absolute value symbols.

  7. If 3 − x < 0 ,  solve | 3 − x|  + 7 = 2x for x.

  8. Solve | x − 4|  + 6 = 3x for x. (Be careful!)

  9. Show that (x − y)3 =  − (y − x)3 . 

  10. Is division associative? That is, is it true (if b ≠ 0 , c ≠ 0) that (a ÷ b) ÷ c = a ÷ (b ÷ c) ? 

  11. What is the ratio of 8 × 10 − 3 to 2 × 104 ? 

  12. What is the ratio of 4 + 36 to 4 ? 

In Exercises 137154, solve the given problems. All data are accurate to two significant digits unless greater accuracy is given.

  1. A certain engine produces 250 hp. What is this power in kilo-watts (kW)?

  2. The pressure gauge for an automobile tire shows a pressure of 32 lb / in . 2 .  What is this pressure in N / m2 ? 

  3. A certain automobile engine produces a maximum torque of 110 N ⋅ m .  Convert this to foot pounds.

  4. A typical electric current density in a wire is 1.2 × 106 A / m2 (A is the symbol for ampere). Express this in mA / cm2 . 

  5. Two computer software programs cost $190 together. If one costs $72 more than the other, what is the cost of each?

  6. A sponsor pays a total of $9500 to run a commercial on two different TV stations. One station charges $1100 more than the other. What does each charge to run the commercial?

  7. Three chemical reactions each produce oxygen. If the first produces twice that of the second, the third produces twice that of the first, and the combined total is 560 cm3 ,  what volume is produced by each?

  8. In testing the rate at which a polluted stream flows, a boat that travels at 5.5 mi/h in still water took 5.0 h to go downstream between two points, and it took 8.0 h to go upstream between the same two points. What is the rate of flow of the stream?

  9. The voltage across a resistor equals the current times the resistance. In a microprocessor circuit, one resistor is 1200 Ω  greater than another. The sum of the voltages across them is 12.0 mV. Find the resistances if the current is 2.4μA in each.

  10. An air sample contains 4.0 ppm (parts per million) of two pollutants. The concentration of one is four times the other. What are the concentrations?

  11. One road crew constructs 450 m of road bed in 12 h. If another crew works at the same rate, how long will it take them to construct another 250 m of road bed?

  12. The fuel for a two-cycle motorboat engine is a mixture of gasoline and oil in the ratio of 15 to 1. How many liters of each are in 6.6 L of mixture?

  13. A ship enters Lake Superior from Sault Ste. Marie, moving toward Duluth at 17.4 km/h. Two hours later, a second ship leaves Duluth moving toward Sault Ste. Marie at 21.8 km/h. When will the ships pass, given that Sault Ste. Marie is 634 km from Duluth?

  14. A helicopter used in fighting a forest fire travels at 105 mi/h from the fire to a pond and 70 mi/h with water from the pond to the fire. If a round-trip takes 30 min, how long does it take from the pond to the fire? See Fig. 1.23.

    A diagram of a helicopter traveling at 105 miles per hour from a fire to a pond, and then traveling at 70 miles per hour from the pond to the fire. The total trip is 30 minutes.

    Fig. 1.23

  15. One grade of oil has 0.50% of an additive, and a higher grade has 0.75% of the additive. How many liters of each must be used to have 1000 L of a mixture with 0.65% of the additive?

  16. Each day a mining company crushes 18,000 Mg of shale-oil rock, some of it 72 L/Mg and the rest 150 L/Mg of oil. How much of each type of rock is needed to produce 120 L/Mg?

  17. An architect plans to have 25% of the floor area of a house in ceramic tile. In all but the kitchen and entry, there are 2200 ft2 of floor area, 15% of which is tile. What area can be planned for the kitchen and entry if each has an all-tile floor?

  18. A karat equals 1/24 part of gold in an alloy (for example, 9-karat gold is 9/24 gold). How many grams of 9-karat gold must be mixed with 18-karat gold to get 200 g of 14-karat gold?

  19.  In calculating the simple interest earned by an investment, the equation P = P0 + P0rt is used, where P is the value after an initial principal P0 is invested for t years at interest rate r. Solve for r, and then evaluate r for P = $7625 , P0 = $6250 ,  and t = 4.000 years .  Write a paragraph or two explaining (a) your method for solving for r, and (b) the calculator steps used to evaluate r, noting the use of parentheses.

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