Question

Given f(x) = 2x + 9, if f(x) = 15, find x.​

Answer 1

Answer:

x = 3

Step-by-step explanation:

$f(x)=2x+9\\\\\text{Substitute}\ f(x)=15:\\\\15=2x+9\qquad\text{subtract 9 from both isdes}\\\\15-9=2x+9-9\\\\6=2x\qquad\text{divide both sides by 2}\\\\\dfrac{6}{2}=\dfrac{2x}{2}\\\\3=x\to x=3$