Question

For the functions f(x)=8 x 2 +7x and g(x)= x 2 +2x , find (f+g)(x) and (f+g)(3)

Answer 1

(f+g)(x)= 9x² + 9x

(f+g)(3) = 108

Explanation:

f(x)=8x² +7x

g(x)= x² +2x

(f+g)(x) = f(x) + g(x) = 8x² +7x +x² +2x = 9x² + 9x

(f+g)(x)= 9x² + 9x

(f+g)(3)= 9*3² + 9*3 = 108