a.(x-1)3-(x-1).(x2x1) b.(x-3)3-(x-3).(x23x9)6(x1)2

Question

a.(x-1)^3-(x-1).(x^2+x+1) b.(x-3)^3-(x-3).(x^2+3x+9)+6(x+1)^2

dananhnhu2k4 · Answer

a) (x - 1)&sup3; - (x - 1)(x&sup2; + x + 1)     = (x - 1)&sup3; - (x&sup3; - 1)     = x&sup3; - 3x&sup2; + 3x - 1 - x&sup3; + 1     = -3x&sup2; + 3x      b) (x - 3)&sup3; - (x - 3)(x&sup2; + 3x +9) + 6(x + 1)&sup2;     = (x - 3)&sup3; - (x&sup3; - 27) + 6(x&sup2; + 2x + 1)     = x&sup3; - 9x&sup2; + 27x - 27 - x&sup3; + 27 + 6x&sup2; + 12x + 6     = -3x&sup2; + 39x + 6

haianhtu97 · Answer

Giải đáp:           Lời giải và giải thích chi tiết:       a) ( x - 1 )&sup3; - ( x - 1 )( x&sup2; + x + 1 )       = ( x - 1 ) [ ( x - 1 )&sup2; - x&sup2; - x - 1 ]       = ( x - 1 ) ( x&sup2; - 2x + 1 - x&sup2; - x - 1 )       = -3x ( x - 1 )       = -3x&sup2; + 3x       b) ( x - 3 )&sup3; - ( x - 3 )( x&sup2; + 3x + 9 ) + 6 ( x + 1 )&sup2;       = x&sup3; - 9x&sup2; + 27x - 27 - ( x&sup3; - 27 ) + 6 ( x&sup2; + 2x + 1 )       = x&sup3; - 9x&sup2; + 27x - 27 - x&sup3; + 27 + 6x&sup2; + 12x + 6       = 39x - 3x&sup2; + 6

a.(x-1)^3-(x-1).(x^2+x+1) b.(x-3)^3-(x-3).(x^2+3x+9)+6(x+1)^2

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