Question

F(x) = 2x2 – 5x – 20 Find f (-9​

Answer 1

`f( - 9) = 187`

Explanation:

`f(x) = {2x}^(2) - 5x - 20`

To find f(-9) , substitute the value of x that's -9 into f(x). That is for every x in f (x) replace it with - 9

We have

`f( - 9) = 2 ({ - 9})^(2) - 5( - 9) - 20 \\ = 2(81) + 45 - 20 \\ = 162 + 25 \: \: \: \: \: \: \: \: \: \: \: \: \: \:`

We have the final answer as

`f( - 9) = 187`

Hope this helps you