15X -135 +18X = 45+90-18X+15X
33X -135 = 135-3X
33X+3X =135+135
36X =270
X=270/36 saco mitad =135/18 saco tercera =45/6 saco tercera =15/2
X=15/2
2(X+3) = 5(X-1)
2X+6 =5X-5
6+5=5X-2X
11=3X
11/3 =X
2(2-5)=5(X+3)
2*(-3) =5X+15
-6 =5X+15
-6-15 =5X
-21=5X
-21/5=X