algebra grade 8

Question

1.(2x^2-4)(2x^2+4)
2.(5yz+6x^2)(5yz-6x^2)
3.(x^2+y^2)(x^2-y^2)

Answer 1

these are just difference-of-squares exercises. recall that

(a-b)(a+b) = a^2-b^2

So,

#1: (2x^2)^2 - 4^2 = 4x^4 - 16

now try the others.