(4x-3y)^2-(2x+y)(3x-5y)
16x^2-24xy+9y^2-(6x^2-10xy+3xy-5y^2)
16x^2-24xy+9y^2-6x^2+10xy-3xy+5y^2
10x^2-17xy+14y^2
(4x-3y)^2-(2x+y)(3x-5y)
16x^2-24xy+9y^2-(6x^2-10xy+3xy-5y^2)
16x^2-24xy+9y^2-6x^2+10xy-3xy+5y^2
10x^2-17xy+14y^2