Question

А)81-а²
Б)25x²-10xy+y²
В)5x²-5y2

Answer 1

a). 81-a^2=(9-a)(9+a); б).25x^2-10xy+y^2=(5x-y)^2; в). 5x^2-5y^2=5(x^2-y^2)=5(x-y)(x+y).