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

Toán Lớp 8: thực hiện phép tính a) 2(2x+5) ∧2 – 4(3+x) ∧2 +2x(x-5) b) 4(x+1) ∧2 + (2x-1) ∧2 – 8(x-1) (x+1)

Toán Lớp 8: thực hiện phép tính
a) 2(2x+5) ∧2 – 4(3+x) ∧2 +2x(x-5)
b) 4(x+1) ∧2 + (2x-1) ∧2 – 8(x-1) (x+1)

Comments ( 2 )

  1. Đáp án:
     
    Giải thích các bước giải:
     

    toan-lop-8-thuc-hien-phep-tinh-a-2-2-5-2-4-3-2-2-5-b-4-1-2-2-1-2-8-1-1

  2. a)
    2(2x+5)^2-4(x+3)^2+2x(x-5)
    =2(4x^2+20x+25)-4(x^2+6x+9)+2x^2-10x
    =8x^2+40x+50-4x^2-24x-36+2x^2-10x
    =(8x^2-4x^2+2x^2)+(40x-24x-10x)+(50-36)
    =6x^2+6x+14
    b)
    4(x+1)^2+(2x-1)^2-8(x-1)(x+1)
    =4(x^2+2x+1)+4x^2-4x+1-8(x^2-1)
    =4x^2+8x+4+4x^2-4x+1-8x^2+8
    =(4x^2+4x^2-8x^2)+(8x-4x)+(4+1+8)
    =4x+13
     

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

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