Question

Let f(x) = -2x - 7 and g(x) = -4x + 6. find g of f (-5)

Answer 1

You can do this one of two methods:

1. Find f(-5) then find g of that number
2. Find an equation for g(f(x)) and put -5 in

1. f(-5)=-2(-5)-7=3
g(3)=-4(3)+6=-6

2. g(f(x))=-4(-2x-7)+6=8x+34
g(f(-5))=8(-5)+34=-6

Both result in the same answer, take your pick :)

Answer 2

still confused

Answer 3

Do you understand how a function works? You put one number in and get a new number out. g(f(x)) means you put x through f to get a new number out, then you put that new number through g.

Answer 4

i got it

Answer 5

if f(x)=3x+2, what is the equation for f–1(x)?