251. (A-b)³=a³-3a²b+3abz-b³
252. Ա)(x-y)³=3x²y+3xy²-y³
Բ) m³-3m².n+3m.nz-n³=(m-n)³
254.
Բ)(x-1)³=x³-3x²+3×1
Գ)(x-2)³=x³-3.x²2+3×2²-2²=x³-6×2+12x-8
Դ)(x-3)³=x³-9x²+27x-27
255)Ա)(a+b)=a³+3a²b+3ab2+b³
Բ)(a-d)³=
Գ)(a+2)²=a³+3a²2+3a.4+8=a³+6a²+17a+8
Դ)(a-2)³=a³-3a²2+3a.4+8=a³-6a²+12a-8
Ե)(a+3)³=a³+9a²+27a+27
Է)(a-4)³=a³-12a³+3ba+67
Թ)(2a+b)³=8a³a+3.(2a)².b+3.(2a)².b+63=b³=8a³+12a².b+6ab²+b³