Question

Given `g(x) = 5x^2 - 4x` and `h(x) = 3x + 9` how do you find g(h(x))?

Answer 1

This means that you must plug in h into g

Explanation:

g(h(x)) = g(3x + 9)

= `5(3x + 9)^2 - 4(3x + 9)`

= `5(9x^2 + 54x + 81 ) - 12x - 36`

= `45x^2 + 270x + 405 - 12x - 36`

= `45x^2 + 258x + 369`

Hopefully this helps!

Answer 2

`g(h(x))=45x^2+258x+369`

Explanation:

`g(x)=5x^2−4x` , `h(x)=3x+9`
`g(h(x))=g(3x+9)`
`=5(3x+9)^2-4(3x+9)`
`=5(9x^2+54x+81)-12x-36`
`=45x^2+270x+405-12x-36`
`=45x^2+258x+369` => expanded form

`3(15x^2 + 86x + 123)`
`=3(15x+41)(x+3)`=> factored form