Question

what should be added to 15 x+13xy+5y^2 to obtain -7x+12xy-6y^2

Answer 1

$\huge\sf\red{Answer}$

$\sf = 15 x+13xy+5y^2\: to \:obtain\: -7x+12xy-6y^2$

$\sf =-7x+12xy-6y^2 - (15 x+13xy+5y^2)$

$\sf =-7x+12xy-6y^2 -15x-13xy-5y^2$

$\sf= -22x -1xy -11$

$\sf =-1(22x +xy +11)$