Question

If f(x)= x-5 and g(x)= -3x + 2, find f(g(«)

Answer 1

Let:

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

and

`g(x)=-3x+2`

then the compositive f(g(x)) would be:

`f(g(x))=f(-3x+2)=(-3x+2)^2-5`

this is equivalent to:

`f(g(x))=f(-3x+2)=((-3x)^2-2(6x)+4)^{}-5`

this is equivalent to

`f(g(x))=f(-3x+2)=9x^2-12x+4^{}-5\text{ = }9x^2-12x\text{ -1}`

then the correct answer is the last one, that is:

`f(g(x))\text{= }9x^2-12x\text{ -1}`