а2+2a-5a-10 = a2-3a-10
y'=3*(sinx)^2*(sinx)'=3*(sinx)^2*cosx
(a+4b)^2−(b−3a)^2=(a+4b+b-3a)(a+4b-b+3a)=
(5b-2a)(3b+4a)=15b^2-6ab+20ab-8a^2=-8a^2+14ab+15b^2