\(3(-7p+9q)=-21p+27q\)

\(-3+(6x+5)=-3+6x+5=6x+2\)

\(-3-(-9a-2)=-3+9a+2=9a-1\)

\(7(-6x+8)=-42x+56\)

\(3(9a+4)+2(-8a+7)=27a+12-16a+14=11a+26\)

\(-5a(-2a+6)=10a^2-30a\)

\((8a+2)+(5a+3)=8a+2+5a+3=13a+5\)

\((2x-4)-(-7x-9)=2x-4+7x+9=9x+5\)

\(-6(9p+5q-7)=-54p-30q+42\)

\((-8x-6)(-2y+7)=16xy-56x+12y-42\)

\((9x-8)(-5x+2)=-45x^2+18x+40x-16=-45x^2+58x-16\)

\((a+7)(a+3)=a^2+3a+7a+21=a^2+10a+21\)

\((a-6)^2=a^2-12a+36\)

\((-3a+8)^2=9a^2-48a+64\)

\((7x-4y)^2=49x^2-56xy+16y^2\)

\((x-5)(x+8)(x+2)=(x-5)(x^2+10x+16)=x^3+10x^2+16x-5x^2-50x-80=x^3+5x^2-34x-80\)

\(p(p+9)(p-8)=p(p^2+p-72)=p^3+p^2-72p\)

\((-5x-4y)(-5x+4y)=25x^2-16y^2\)

\((8a-2)(8a+2)=64a^2-4\)

\((a-5)(a+5)=a^2-25\)