a)
7-2x=5x+28
-2x-5x= 28-7
-7x= 21/:(-7)
x = -3
b)
6x+2x-10=3x+5
6x+2x-3x= 5+10
5x= 15/:5
x= 3
c)
3(9+2x)=5x+31
27 + 6x=5x+31
6x-5x= 31-27
x= 4
d)
-17x+4(x-7)= -3(3x-1)+1
-17x+4x-28= -9x+3+1
-17x+4x+9x = 3+1 +28
-4x= 32/:(-4)
x= -8
