a.
\(=xy\left(x+xy-y\right)\)
b.
\(3xy-6y+x^2-2x=3y\left(x-2\right)+x\left(x-2\right)\)
\(=\left(3y+x\right)\left(x-2\right)\)
c.
\(x^2-12x+36-64y^2=\left(x-6\right)^2-\left(8y\right)^2\)
\(=\left(x-6+8y\right)\left(x-6-8y\right)\)
d.
\(x^2+7x+10=x^2+2x+5x+10=x\left(x+2\right)+5\left(x+2\right)\)
\(=\left(x+2\right)\left(x+5\right)\)