algebra help please

Question

Let f(x)=2x^2 –7 and g(x)=x–4.

 

find (f o g)(-1). show work

Answer 1

I'll show you two ways to do this and you pick which you like.

 

g(-1) = -1 - 4 = -5

 

f(-5) = 2(-5)² - 7 = 2(25) - 7 = 50 - 7 = 43

 

Or...

 

f(g(-1)) = 2(-1 - 4)² - 7 = 2(-5)² - 7 = 2(25) - 7 = 50 - 7 = 43