Объяснение:
Обрезаны уcловия:
(m-n)/m^2 -(n-m)/(mn)=(n(m-n)-m(n-m))/(m^2 •n)=(n(m-n)+m(m-n))/(nm^2)=(m-n)(n+m)/(nm^2)=(m^2 -n^2)/(nm^2)
4/(c^2 -9) -2/(c^2+3c)=4/((c-3)(c+3)) -2/(c(c+3))=(4c-2(c-3))/(c(c-3)(c+3))=(4c-2c+6)/(c(c-3)(c+3))=(2c+6)/(c(c-3)(c+3))=2(c+3)/(c(c-3)(c+3))=2/(c(c-3))=2/(c^2 -3c)
42/(x^2 +7у) -6/у=(42у-6(х^2 +7у))/(у(х^2 +7у))=(42у-6х^2 -42у)/(у(х^2 +7у))=-(6х^2)/(у(х^2 +7у))=-(6х^2)/(ух^2 +7у^2)
6b/(3-b) -2b=(6b-2b(3-b))/(3-b)=(6b-6b+2b^2)/(3-b)=(2b^2)/(3-b)
1/(х+2) +2/(х^2 -2х) -4/(4-х^2)=1/(х+2) +2/(х(х-2)) +4/((х-2)(х+2))=(х(х-2)+2(х+2)+4х)/(х(х-2)(х+2))=(х^2 -2х+2х+4+4х)/(х(х-2)(х+2))=(х^2 +4х+4)/(х(х-2)(х+2))=((х+2)^2)/(х(х-2)(х+2))=(х+2)/(х(х-2))=(х+2)/(х^2 -2х)
(a+2b)/a=1 +2b/a
{y= -x-2
сложим
2у=-4
у=-2
х=у+2=0
(0;-2)