Question

If f(x)=49-x^2 and g(x)=7-x, which is the rule of the function (f-g)(x)?

A. -x^2-x-56
B. -x^2+x+42
C. 7+x
D. x^3-7x^2-49x=343

Answer 1

B

Explanation:

(f - g)(x) = f(x) - g(x), then

f(x) - g(x)

= 49 - x² - (7 - x) ← distribute by - 1

= 49 - x² - 7 + x ← collect like terms

= - x² + x + 42 → B