[tex](x+3)(x-2) = x^2-2x+3x-6 = x^2 +x -6[/tex]
[tex](x-3y)(x+2y-6) = x^2 +2xy -6x - 3xy -6y^2 +18y = x^2 -6y^2-xy -6x +18y[/tex]
[tex](3x+2y-5)(x-4y+3) = 3x^2 -12xy +9x +2xy -8y^2 +6y -5x +20y-15 = 3x^2 +4x -10xy -8y^2 +26y-15[/tex]
