How to factor 7x^2+27xy-4y^2
7x^2+27xy-4y^2
7*-4=-28
I need to numbers that add to 27 and mult to -28
They are 28 and -1
\(7x^2+28xy-1xy-4y^2\\ =7x(x+4y)-y(x+4y)\\ =(7x-y)(x+4y)\)
