Question

For the functions f(x)=2x^2+3x+9 and g(x)=−3x+10 find (f⋅g)(x) and (f⋅g)(1)

Answer 1

Step-by-step explanation:

f(x)=2x²+3x+9

g(x) = - 3x + 10

In order to find (f⋅g)(1) first find (f⋅g)(x)

To find (f⋅g)(x) substitute g(x) into f(x) , that's for every x in f (x) replace it by g (x)

We have

(f⋅g)(x) = 2( - 3x + 10)² + 3(- 3x + 10) + 9

Expand

(f⋅g)(x) = 2( 9x² - 60x + 100) - 9x + 30 + 9

= 18x² - 120x + 200 - 9x + 30 + 9

Group like terms

(f⋅g)(x) = 18x² - 120x - 9x + 200 + 30 + 9

(f⋅g)(x) = 18x² - 129x + 239

To find (f⋅g)(1) substitute 1 into (f⋅g)(x)

That's

(f⋅g)(1) = 18(1)² - 129(1) + 239

= 18 - 129 + 239

We have the final answer as

(f⋅g)(1) = 128

Hope this helps you