\(7(9x+4y)=63x+28y\)

\(-6+(3p+9)=-6+3p+9=3p+3\)

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

\(5(-6a+7)=-30a+35\)

\(2(-8x+9)-4(-7x+5)=-16x+18+28x-20=12x-2\)

\(3a(7a-4)=21a^2-12a\)

\((5x+8)+(4x-9)=5x+8+4x-9=9x-1\)

\((4a+8)-(-3a+6)=4a+8+3a-6=7a+2\)

\(-3(-8p+9q+5)=24p-27q-15\)

\((9x+4)(8y-3)=72xy-27x+32y-12\)

\((3a+5)(-2a+8)=-6a^2+24a-10a+40=-6a^2+14a+40\)

\((a-6)(a-8)=a^2-8a-6a+48=a^2-14a+48\)

\((x-9)^2=x^2-18x+81\)

\((8x-4)^2=64x^2-64x+16\)

\((8p-4q)^2=64p^2-64pq+16q^2\)

\((x+2)(x+5)(x-4)=(x+2)(x^2+x-20)=x^3+x^2-20x+2x^2+2x-40=x^3+3x^2-18x-40\)

\(a(a+4)(a+3)=a(a^2+7a+12)=a^3+7a^2+12a\)

\((-5a+4b)(-5a-4b)=25a^2-16b^2\)

\((-9x-3)(-9x+3)=81x^2-9\)

\((p+9)(p-9)=p^2-81\)