1. х^2+5х+6х+30=х^2+11х+30
2.15b-6b^2-10+4b+6b=25b-6b^2-10
3.a^2+2ab-3ab-6b^2+5a^2+2ab=6a^2+ab-7b^2
4. 8am-24m+an-3n
5.2x^2-16x=2x^2-3x+2x-3
2x^2-2x^2-16x+3x-2x=-3
-15x=-3
x=5