Answer:
Add -4x to both sides--> 6x+9=4x-3 and 2x+9=-3
multiply both sides by -1/4 --> -4(5x+7)=-18 and 5x-7=4.5
multiply both sides by 1/4--> 12x+4=20x+24 and 3x+1=5x+6
multiply both sides by -4--> -5x/4=4 and 5x=-16
add -4 to both sides--> 8-10x=7+5x and 4-10x=3+5x