Question

(2.5p-1.5q)²-(1.5p-2.5q)²

Answer 1

using identity a² - b² = (a+b)(a-b)
=[ (2.5p-1.5q) + (1.5p - 2.5q)] [(2.5p-1.5q) - (1.5p-2.5q) ]
(2.5p-1.5q+1.5p-2.5q)(2.5p-1.5q-1.5p+2.5q)

(4p-4q)(p+q)

hope this helps you