Solve equations
12 + b = 42
M - 12 = - 16
-224= 4 x
-3= b over 12
V over 4 = 12
2( n+ 3)=- 12
-3+ x over 5 =-8
-2= x+2 over 6
2(n+6)=-8
-3 x-20= -155