Hi there! :)
4x + 5x + 12 = 6(x - 2)
Combine like terms and distribute the coefficient outside of the parenthesis:
9x + 12 = 6(x) + 6(-2)
9x + 12 = 6x - 12
Subtract 6x from both sides:
9x - 6x + 12 = 6x - 6x - 12
3x + 12 = -12
Subtract 12 from both sides:
3x + 12 - 12 = -12 - 12
3x = -24
Divide both sides by 3:
3x/3 = -24/3
x = -8.