Question

Find fog(x) when f(x) = 2x² + x and g(x) = 3x + 2

Answer 1

For fog or f(g(x)), plug g(x) into f(x):

2(3x+2)²+x

Then simplify:

2( (3x+2)(3x+2) )+x

2( 9x²+12x+4 )+x

18x²+24x+8 +x

18x²+25x+8

Then you can simplify this further using factoring methods to:

(2x+1)(9x+8)

Hope this helps!! :)