Question

Given `f(x) = 4x + 5` and `h(x) = sqrt(5x - 4)` how do you find (hf)(4)?

Answer 1

`( hf)(4) =sqrt 101`

Explanation:

`f(x)= 4 x+5 , h(x)= sqrt (5 x-4)`

`(hf)(x)=h(f(x)) = h ( 4 x +5) = sqrt ( 5(4 x+5)-4)`

`(hf)(4) = sqrt ( 5(4*4+5)-4) = sqrt (105-4) =sqrt 101`

`:.( hf)(4) =sqrt 101` [Ans]