1) 4х-4+3х+6=7х+21
0=15 - невозможно, корней нет
2) 2х+2+3х-9=5х-7
-7=-7 - корней (-∞;+∞)
3) 2х^2-2х+х-1-2х^2+х-2х+1=24
-2х=24
х=-12
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A) b/a+b * a^2-b^2/b^2 = b * (a-b)(a+b)/(a+b)*b^2 = a-b/b
б) 2x-2y/y : x^2-y^2/y^2 = 2(x-y)*y^2/y*(x-y)(x+y) = 2y/x+y
в) (-2a^2/b)^3 = -8a^6 / b^3
г) 3ab * a^2/b = 3ab*a^2/b
X2-3x+9/(х+3)(х2-3х+9) - х2+18/х2+27=х2-3х+9-х2-18/(х+3)х2-3х+9)=-9-3х(х+3)(х2-3х+9)=
=-3(х+3)/(х+3)(х2-3х+9)= 3/х2-3х+9