Test #1 Review Ch 6 Exercise 6.3 b)

Chapter 6 Textbook Exercise 6.3 Question b)

Let f(x) = 2x-3 and g(x) = 3x² + 4x. Find the following composition g(f(2)):

First find g(f(x))

g(f(x)) = g(2x-3)

= 3(2x-3)² + 4(2x-3)

= 3(4x²-12x+9) +8x -12

= 12x² -36x +27 +8x -12

g(f(x))  = 12x² -28x +15

Now we can solve for g(f(2))

g(f(2))  = 12(2)² -28(2) +15

= 12(4) – 56 +15

= 48 -56 +15

g(f(2))  = 7