Answer:
Step-by-step explanation:
f(x) is like y in a linear equation. There is one major difference. F(x) tells you what to substitute on the right every time you see an x.
f(a) = -3a + 7
f(b) = -3b + 7
For this question a and b have values. Now work with the right side only. This is the quickest way to get the answer, but it is only marginally correct.
f(a) = -3(-8) + 7 = 24 + 7 = 31
f(b) = -3(7) + 7 = -21 + 7 = - 14
f(a) + f(b) = 31 - 14 = 17
f(a) - f(b) = 31 - (-14) = 31 + 14 = 45
