-12 + 3.( - x + 7 ) = -18
3.( - x + 7 ) = -18 - (-12)
3.( - x + 7 ) = -6
( - x + 7 ) = -6 : 3
- x + 7 = -3
-x = -3 -7
-x = -10
3.(-x+7)=(-18)-(-12)=30
(-x)+7=30:3=10
(-x)=10-7=3
x=3
-12+3.(-x+7)= -18
3.(-x+7)= -18-(-12)
3.(-x+7)= -6
(-x+7)= -6:3
-x+7= -2
-x = -2-7
-x = -9
-12+3.(x+7)=-18
3.(x+7)=-18+12
3.(x+7)=-6
x+7=-6:3
x+7=-2
x=-2-7
x=-9