Answer :
[tex] \frac{9x - 15}{4} = x[/tex] / * 4 (both sides)
9x - 15 = 4x / - 9x (both sides)
-15 = -5x / ÷ (-5) (both sides)
x = 3
9x - 15 = 4x / - 9x (both sides)
-15 = -5x / ÷ (-5) (both sides)
x = 3