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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: RÚT GỌN BIỂU THỨC N= (4x+4)^2 + 8(x-3) (1+x) + x^2 – 6x +9

Toán Lớp 8: RÚT GỌN BIỂU THỨC
N= (4x+4)^2 + 8(x-3) (1+x) + x^2 – 6x +9

Comments ( 2 )

  1. N=(4x+4)^2+8(x-3)(1+x)+x^2-6x+9
    =[4(x+1)]^2+8(x+1)(x-3)+x^2-2.x.3+3^2
    =[4(x+1)]^2+2.4.(x+1)(x-3)+(x-3)^2
    =[4(x+1)+(x-3)]^2
    =(4x+4+x-3)^2
    =(5x+1)^2
    =(5x)^2+2.5x.1+1^2
    =25x^2+10x+1
    Áp dụng hằng đẳng thức:
    (A+B)^2=A^2+2AB+B^2
    (A-B)^2=A^2-2AB+B^2

  2. $AkaShi
    (4x+4)^2+8(x-3)(1+x)+x^2-6x+9
    =16x^2+32x+16+(8x-24)(1+x)+x^2-6x+9
    =16x^2+32x+16+8x^2-16x-24+x^2-6x+9
    =(16x²+8x²+x²)+(32x-16x-6x)+(16-24+9)
    =25x²+10x+1
     

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222-9+11+12:2*14+14 = ? ( )

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