b) (–2x – 5y)(2x – 5y);
b) (–2x – 5y)(2x – 5y);
b) (–2x – 5y)(2x – 5y)= ‒[(2x + 5y)(2x – 5y)]
= ‒ [(2x)2 ‒ (5y)2] = ‒(4x2 ‒ 25y2) = 25y2 ‒ 4x2.