Question

Expand and simplify: [(2x-3y)(2x+3y)-(3x+2y)(3x-2y)]^2

Answer 1

$((2x-3y)(2x+3y)-(3x+2y)(3x-2y))^2\\((4x^2+6xy-6xy-9y^2)-(9x^2-6xy+6xy-4y^2))^2\\((4x^2-9y^2)-(9x^2-4y^2))^2\\(-5x^2-5y^2)^2\\(-5x^2-5y^2)(-5x^2-5y^2)\\25x^4+25x^2y^2+25x^2y^2+25y^4\\25x^4+50x^2y^2+25y^4$

25x^4+50x^2y^2+25y^4