Question

Find f(g(x))Let f(x)=5x-7, g(x)=3x+2

Answer 1

SOLUTION

Step1: write out the giving information

$\begin{gathered} f(x)=5x-7 \\ \text{and } \\ g(x)=3x+2 \end{gathered}$

Step2: write out f(g(x))

$f(g(x))\text{ means to substitute g(x) for x in f(x)}$

Hence we have

$f(g(x))=5(3x+2)-7$

Step3: simplify the expression above, we have

$\begin{gathered} f(g(x))=15x+10-7 \\ =15x+3 \end{gathered}$

Therefore, the expression for f(g(x)) is 15x+3