f(x)=g(x)
7x+6=3x-18 What you'll do next is transpose 3x and 6 7x-3x=-18-6 (they become negative because when you transpose you have to change signs. Which means if the number is positive, you change it to negative, and vise versa) 4x=-24
Then divide both sides by 4.
The final answer is. X = -6
