(7+x)*3=21+3x
(9-x)*2=18-2x
5(3-x)=15-5x
x(6-a)=6x-ax
12(3-11x-y)=36-132x-12y
(15+2x+4y)*6=90+12x+24y
(2+x)*6=12+6x
(3-x)*15=45-15x
4(3-x)=12-4x
x(7-a)=7x-ax
9(2-11x-y)=18-99x-9y
(16+7x+8y)*2=32+14x+16y