2a(a+5)-(a-7)2
-(b-2)(b+2)-2(b+4)(b+2)
-(b-2)(b+2)-2(b+4)(b+2) = 2a^2+10a-2a+14-(b^2-4)-2(b^2+2b+4b+8) = 2a^2+8a+14-b^2-4-2b^2-4b-8b-16 = 2a^2+8a+14-2b^2-12b-20 = 2a^2 + 8a-2b^2-12b-6