142
1) (2-3х)(4+6х+9х²)+3х(3х-1)(3х+1)=х
2³-(3х)³ + 3х((3х)²-1) - х = 0
8-27х³+27х³-3х-х=0
-4х = -8
х = 2
2) 27(1/3 х - 1)(1/9 х² + 1/3 х + 1) - х(х-1)² = 2х²
27((1/3 х)³ - 1) - х(х²-2х+1) - 2х² = 0
х³-27-х³+2х²-х-2х²=0
-х = 27
х = -27
143
1) (а+3)³ -27 = ((а+3)-3)((а+3)²+(а+3)*3+3²) =
= (а+3-3)(а²+6а+9+3а+9+9) = а(а²+9а+27)
2) (а-7)³+8 = ((а-7)+2)((а-7)²-(а-7)*2+2²) =
= (а-7+2)(а²-14а+49-2а+14+4) = (а-5)(а²-16а+67)