Question

Question #79cc2

Answer 1

`f(-2)=14`

Explanation:

`f(x)=kx^2-5x-4`

Firstly, to find the value of `k` substitute in `f(4)=8`

`8=k4^2-5*4-4`
`8+4+20=16k`
`32=16k`
`k=2`

`therefore f(x)=2x^2-5x-4`

Substituting in the values of `x`
`f(-2)=2*(-2)^2-5*(-2)-4`
`f(-2)=2*4+5*2-4`
`f(-2)=8+10-4`
`f(-2)=14`