Môn Toán Lớp 8: Ptích đa thức - ntử a)16x-5x2-3 b)x4x3x1 c)4(x3)2-(2x-3)2 d)2x(xy)-4x-4y e)x3-xy3-y f)x3x3x2y3xy2y3y g)2(x5)-x2-5x Ét o ét

Question

Môn Toán Lớp 8:  Ptích đa thức -> ntử a)16x-5x2-3 b)x4+x3+x+1 c)4(x+3)2-(2x-3)2 d)2x(x+y)-4x-4y e)x3-x+y3-y f)x3+x+3x2y+3xy2+y3+y g)2(x+5)-x2-5x Ét o ét!!!!

ankim · Answer

Giải đáp:   a) 16x-5x&sup2;-3   = -5x&sup2;+16x-3   =-(5x&sup2; -16x +3)   =-( 5x&sup2;-15x-x+3)   =-(5x( x-3)-(x-3))   =(x+3)(5x-1)   b)x4 + x3 +x +1   = x3(x+1) +(x+1)   =(x+1)(x3 +1)   c) 4(x+3)&sup2;-(2x-3)&sup2;     =4(x&sup2;+6x+9)-(4x&sup2;-12x+9)     =4x&sup2;+24x+36-4x&sup2;+12x-9     =36x+27     =9(4x+3)    d) 2x(x+y)-4x-4y     = 2x(x+y)-4(x+y)     =(2x-4)(x+y)     e) x&sup3; - x +y&sup3;-y     =(x&sup3;-y&sup3;)-(x+y)     =(x+y)(x&sup2; -xy+y&sup2;)-(x+y)     =(x+y)(x&sup2; -xy+y&sup2;-1)     f)x&sup3;+x+3x&sup2;y+3xy&sup2;+y&sup3;+y     =(  x&sup3;+3x&sup2;y+3xy&sup2;+y&sup3;)+(x+y)     =(x+y)&sup3; +(x+y)     =(x+y)(x&sup2;+2xy+y&sup2;+1)     g) 2(x+5)-x&sup2;-5x      = 2(x-5)-x(x-5)     =(x-5)(2-x)

hiennhi98 · Answer

Giải đáp:+Lời giải và giải thích chi tiết:    a)16x-5x&sup2;-3   =15x-5x&sup2;-x-3   =5x(3-x)-(3-x)   =(3-x)(5x-1)   b)x^4+x&sup3;+x+1   = (x^4-x^3)-(x^2-1)   = x^3(x - 1)-(x - 1)(x + 1)   = (x - 1)(x^3-x-1)   c)4(x+3)&sup2;-(2x-3)&sup2;   =[2(x+3)-(2x-3)][2(x+3)+(2x-3)]   =(2x+6-2x+3)(2x+6+2x-3)   =9(4x+3)   d)2x(x+y)-4x-4y   =2x(x+y)-4(x+y)   =(x+y)(2x-4)   =2(x-2)(x+y)   e)x&sup3;-x+y&sup3;-y   =(x&sup3;+y&sup3;)-(x+y)   =(x+y)(x&sup2;+xy+y&sup2;)-(x+y)   =(x+y)(x&sup2;+xy+y&sup2;-1)   f)x&sup3;+x+3x&sup2;y+3xy&sup2;+y&sup3;+y   =(x&sup3;+3x&sup2;y+3xy&sup2;+y&sup3;)+(x+y)   =(x+y)&sup3;+(x+y)   =(x+y)[(x+y)&sup2;+1]   =(x+y)(x&sup2;+2xy+y&sup2;+1)   g)2(x+5)-x&sup2;-5x   =2(x+5)-x(x+5)   =(x+5)(2-x)

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Môn Toán Lớp 8: Ptích đa thức -> ntử a)16x-5×2-3 b)x4+x3+x+1 c)4(x+3)2-(2x-3)2 d)2x(x+y)-4x-4y e)x3-x+y3-y f)x3+x+3x2y+3xy2+y3+y g)2(x+5)-x2-5x Ét o ét

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