Question

Решить систему уравнений: 9/(x-y) - 4/(x+y)=1 , 6/(x-y) + 12/(x+y) =8

Answer 1

(9(х+у)-4(х-у))/((х-у)(х+у))=1, (6(х+у)+12(х-у))/((х-у)(х+у))=8, 9х+9у-4х+4у=х^2-y^2, 6x+6y+12x-12y=8(x^2-y^2), 5x+13y=x^2-y^2, 18x-6y=8(5x+13y), 18x-6y=40x+104y, 18x-40x=104y+6y, -22x=110y, -x=5y, x=-5y, (9(-5y+y)-4(-5y-y))/((-5y-y)(-5y+y))=1, (-36y+24y)/24y^2=1, -12y=24y^2, y=-0,5, 5x+13*(-0,5)=x^2-(-0,5)^2, 5x-6,5=x^2-0,25, x^2-5x+6,25=0, D=(-5)*(-5)-4*6,25*1=25-25=0, x=-(-5)/(2*1)=2,5