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

Toán Lớp 8: tính 3x(2x + 5) +(6x-1)(2-x) +2 x^2 +(3x+1)(5x-3) -(1-4x)^2 giúp miik vs mai mik khảo sát rùi

Toán Lớp 8: tính 3x(2x + 5) +(6x-1)(2-x) +2
x^2 +(3x+1)(5x-3) -(1-4x)^2
giúp miik vs mai mik khảo sát rùi

Comments ( 1 )

  1. 3x.(2x+5)+(6x-1).(2-x)+2
    =3x.2x+3x.5+6x.2-6x.x-1.2+1.x+2
    =6x^2+15x+12x-6x^2-2+x+2
    =(6x^2-6x^2)+(15x+12x+x)+(2-2)
    =0+28x+0
    =28x
    $\\$
    x^2+(3x+1).(5x-3)-(1-4x)^2
    =x^2+3x.5x-3x.3+1.5x-1.3-[1^2+2.1.4x+(4x)^2]
    =x^2+15x^2-9x+5x-3-1-8x-16x^2
    =(x^2+15x^2-16x^2)+(5x-9x-8x)-(3+1)
    =0+(-12x)-4
    =-12x-4
     

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