Verified answer

(p-q)(p+q)=p²-q²

(7+3y)(7-3y)=49-9y²

(8b+5a)(5a-8b)=25a²-64b²

(5x-10y)(5x+10y)=25x²-100y²

(4y+m)(m-4y)=m²-16y²

(x²+m)((m-x²)=m²-x⁴

(a²-4)(a²+4)=a⁴-16

(x³-2y⁴(x³+2y⁴)=x⁶-4y⁸

(0.1a-b)(0.1a+b)=0.01a²-b²

(3/7+6a)(6a-3/7)=36a²-9/21