Question

Review Question: 5) f(x) = 2xsquared + 7x - 15 find f(-8)​

Answer 1

f(-8) = 57

Explanation:

When x = - 8

f(-8) = 2 x (-8)² + 7 x (-8) - 15

f(-8) = 2 x 64 - 56 - 15

f(-8) = 128 - 56 - 15

f(-8) = 128 - 71

f(-8) = 57

Answer 2

`\sf f(x) = 2x^2 + 7x - 1`

Just substitute the value of x as (-8) .

`\sf f(-8) = 2(-8)^2 + 7(-8) - 15`

`\sf f(-8) = 2(64) - 7(8) - 15`

`\sf f(-8) = 128 - 56 - 15`

`\sf f(-8) = 128 - 71`

`\sf f(-8) = 57`