Question

Find the value of: (x+y)(2x-y)-(x-y)(3x-5y)

Answer 1

Answer:

$(x+y)(2x-y)-(x-y)(3x-5y) \\ = ( {2x}^{2} - {y}^{2} ) - ({3x}^{2} + {5y}^{2} ) \\ = {2x}^{2} - {y}^{2} - {3x}^{2} - {5y}^{2} \\ = ( {2x}^{2} - {3x}^{2} ) + ( { - y}^{2} - {5y}^{2} ) \\ = { - x}^{2} + ( { - 6y}^{2} ) \\ = { - x}^{2} - {6y}^{2}$