Помогите сократить дробь: [latex] \frac{12xy-4 x^{2} -5 y^{2} }{2 x^{2} -15 y^{2}+xy } [/latex]

[latex] \frac{12xy-4 x^{2} -5 y^{2} }{2 x^{2} -15 y^{2}+xy } = \frac{-4(x-0,5y)(x-2.5y) }{2(x-2.5y)(x+3y)} = \frac{-2(x-0,5y)(x-2.5y) }{(x-2.5y)(x+3y)} = \frac{-2(x-0,5y) }{(x+3y)} = [/latex] [latex]- \frac{2x-y}{x+3y} [/latex] [latex]12xy-4 x^{2} -5 y^{2}=0[/latex] [latex]-4 x^{2}+12xy -5 y^{2}=0[/latex] [latex]a=-4[/latex] [latex]b=12y[/latex] [latex]c=-5y^2[/latex] [latex]D=(12y)^2-4*(-4)*(-5y)=144y^2-80y^2=64y^2[/latex] [latex]x_1= \frac{-12y+8y}{-8} =0.5y[/latex] [latex]x_2= \frac{-12y-8y}{-8} =2.5y[/latex] [latex]-4x^2+12xy-5y^2=-4(x-0.5y)(x-2.5y)[/latex] [latex]2 x^{2} -15 y^{2}+xy=0[/latex] [latex]2x^2+xy-15y^2=0[/latex] [latex]a=2[/latex] [latex]b=y[/latex] [latex]c=-15y^2[/latex] [latex]D=y^2-4*2*(-15y^2)=121y^2[/latex] [latex]x_1= \frac{-y+11y}{4} =2.5y[/latex] [latex]x_2= \frac{-y-11y}{4} =-3y[/latex] [latex]2x^2+xy-15y^2=2(x-2.5y)(x+3y)[/latex]