-8(-6x-9)=9(-4x-6),
48x+72=-36x-54,
48x+36x=-54-72,
84x=-126,
Divide both sides by 42:
2x=-3, x=-3/2.
CHECK Put x=-3/2 into the original equation:
-8(9-9)=9(6-6), so 0=0 OK.
Another way to solve: rewrite the original equation:
-24(-2x-3)=18(-2x-3) by factorising the contents of the parentheses,
42(-2x-3)=0, so, since 42 is not zero, -2x-3=0, 2x=-3, x=-3/2.