this is the equation: 3x-2=5x+15
you combine like terms: 3x-3x-2=5x-3x+15
the 3x on the left cancles out: -2=2x+15
subtract 15 on both sides: -2-15=2x+15-15
the 15 on the right cancles out:--17=2x
divide by 2: -17/2=2x/2
x equals negative 8.5: x=-8.5