3x + 7 = 5x - 1

6x + 3 = 21

3x - 2x + 7x

Put all xs on one side; all numbers on one side. add the opposite of 3x to both sides. then 7=2x-1 now add 1 to both sides of the equation: then 8=2x; to solve

for x divide both sides by the coefficient of x which is 2. Hence, x=4.

Good luck!