30(x - 10) = 120
Use distributive property to remove the parenthesis
30x - 30(10) = 120
30x - 300 = 120
move the constant to the right side
30x - 300 = 120
30x = 120 + 300
30x = 420
solve for x by moving 30 to the right side, multiplication will be division after moved to the right side
30x = 420
x = 420/30
x = 14
The value of x is 14