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TEST BANK

Precalculus: Mathematics for Calculus

James Stewart , Lothar Redlin , Saleem Watson

8th Edition

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Precalculus: Mathematics for Calculus 9

th Edition Test Bank

Sample Questions Ch. 2 Polynomial and Rational Functions 2.1 Complex Numbers

• Add and Subtract Complex Numbers

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.Add or subtract as indicated and write the outcome in standard form. 1) (5 – 6i) + (9 + 9i)

• 14 + 3i B) 14 – 3i C) -4 + 15i D) -14 – 3i

2) (9 + 5i) – (-8 + i)

• 17 + 4i B) 17 – 4i C) 1 + 6i D) -17 – 4i

3) 8i + (-7 – i)

• -7 + 7i B) -7 + 9i C) 7 – 7i D) 7 – 9i

4) 5i – (-5 – i)

• 5 + 6i B) -5 – 6i C) 5 – 4i D) -5 + 4i

5) (-7 + 6i) – 9

• -16 + 6i B) 16 – 6i C) 2 + 6i D) 2 – 6i

6) -2 – (- 2 – 8i) – (- 2 – 6i)

• 2 + 14i B) 2 – 14i C) 4 – 14i D) 4 + 14i

7) (4 – 3i) + (1 – 6i) + (4 + 5i)

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• 9 – 4i B) 7 + 8i C) 1 – 14i D) 5 – 9i
• Multiply Complex Numbers

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.Find the product and write the outcome in standard form. 1) -5i(3i – 9)

• 15 + 45i B) -15 + 45i C) 45i – 15i2 D) 45i + 15i2

2) 7i(-3i + 6)

• 21 + 42i B) -21 + 42i C) 42i – 21i2 D) 42i + 21i2

3) (9 + 8i)(5 – 5i)

• 85 – 5i B) 85 + 5i C) 5 + 85i D) -40i2 – 5i + 45

4) (-6 + 9i)(5 + i)

• -39 + 39i B) -21 + 39i C) -39 – 51i D) -21 – 51i

5) (8 – 6i)(-5 – 3i)

• -58 + 6i B) -58 – 54i C) -22 + 6i D) -22 – 54i

6) (9 + 3i)(9 – 3i)

• 90 B) 81 – 9i2 C) 72 D) 81 – 9i

Page 1 7) (-4 + i)(-4 – i)

A) 17 B) -4 C) 16 D) -15

8) (4 + 9i)2

• -65 + 72i B) 97 + 72i C) -65 D) 16 + 72i + 81i2

Perform the indicated operations and write the outcome in standard form.9) (7 + 8i)(3 – i) – (1 – i)(1 + i)

• 27 + 17i B) 31 + 17i C) 29 + 17i D) 27 + 31i

10) (2 + i)2 – (6 – i)2

• -32 + 16i B) 32 + 16i C) -48 D) -32 – 16i

Complex numbers are used in electronics to describe the current in an electric circuit. Ohm’s law relates the current in a circuit, I, in amperes, the voltage of the circuit, E, in volts, and the resistance of the circuit, R, in ohms, by the formula E = IR. Solve the problem using this formula.11) Find E, the voltage of a circuit, if I = (8 + 9i) amperes and R = (4 + 7i) ohms.

• (-31 + 92i) volts B) (-31 – 92i) volts C) (92 – 31i) volts D) (92 + 31i) volts

12) Find E, the voltage of a circuit, if I = (18 + i) amperes and R = (2 + 3i) ohms.

• (33 + 56i) volts B) (33 – 56i) volts C) (-18 + 56i) volts D) (-18 – 56i) volts
• Divide Complex Numbers

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

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Divide and express the outcome in standard form. 1) 7

• – i
• 56

65

• 7

65 i B) 56 65 – 7 65 i C) 89

• 19i D) 89

– 19

i 2) 8

• + i
• 16

5

– 85

i B) 16 5

• 85

i C) 16 3

• 83

i D) 16 3

– 83

i 3) 10i

• + i
• 1 + 3i B) -1 + 3i C) 1 + 10i D) 1 – 3i

4) 4i

• + i
• 2

5

• 65

i B) – 25

+ 65

i C) 1 PROFDOC

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