Question

Answer 1

a: \(=\left(a-1\right)^2-b^2=\left(a-1-b\right)\left(a-1+b\right)\)

b: \(=\left(x+y\right)^2-81=\left(x+y-9\right)\left(x+y+9\right)\)

c: \(=\left(x+3\right)^2-y^2=\left(x+3+y\right)\left(x+3-y\right)\)

e: \(=\left(2x-y\right)^2-9=\left(2x-y-3\right)\left(2x-y+3\right)\)