Question

find the product (8x^2-5y)(8x^2+5y) can someone help

Answer 1

Use the identity
(a-b)(a+b) = a^2 - b^2
Now, put a= 8x^2 , b=5y into the identity
(8x^2-5y)(8x^2+5y) = (8x^2)^2 - (5y)^2 = ?