-15 = 6x + 15 -10x
1st. You combine like terms
(6-10)x
-15 = -4x + 15
2nd. You move variables to the left side and change the sign
-15 = -4x + 15
+4x +4x
4x - 15 = 15
+15 +15
4x = 30
3rd. You divide both sides of the equation by 4
(4x) /4 = (30) /4
x= 30/4
4th. Reduce the fraction by 2
30/ 4 = 15/2
Answer is 15/2