Algebra 2 Problems?

1.
(2 + 7i) + (5 - 4i)
= 2 + 7i + 5 - 4i
= (2 + 5) + (7i - 4i)
= 7 + 3i

The answer: B. 7 + 3i


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2.
(f o g)(x)
= f[g(x)]
= f(x² - 3)
= (x² - 3) - 10
= x² - 13

(f o g)(-5)
= (-5)² - 13
= 25 - 13
= 12

The answer: A. (f o g)(-5) = 12


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3.
(x⁴ + 3x² - 12) - (3x³ + 2x² - 4)
= x⁴ + 3x² - 12 - 3x³ - 2x² + 4
= x⁴ - 3x³ + (3x² - 2x²) + (-12 + 4)
= x⁴ - 3x³ + x² - 8

The answer: D. x⁴ - 3x³ + x² - 8


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4.
Interest earned after 3 years
= $540 × 4.5% × 3
= $72.9
≈ $73

The answer: A. Spencer will earn about $73.00.

　
1.

How hard is it to add 2 and 5 and to subtract 4 from 7?

(2 + 7i) + (5 − 4i) = (2+5) + (7i−4i) = 7 + 3i

2.

f(x) = x − 10
g(x) = x² − 3

g(−5) = (−5)²−3 = 22
f(g(−5)) = f(22) = 22−10 = 12

3.

None of the answers listed are correct.
So I suspect you mean: (x^4 + 3x² - 12) - (3x^3 + 2x² - 4)

Again, how difficult is it to add/subtract integer coefficients?

(x⁴ + 3x² − 12) − (3x³ + 2x² − 4)
= x⁴ + 3x² − 12 − 3x³ − 2x² + 4
= x⁴ − 3x³ + (3x² − 2x²) + (−12 + 4)
= x⁴ − 3x³ + x² − 8

4.

Interest = $540 * 3 * 0.045 = $72.90

Sorry , too many questions.