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

Toán Lớp 8: c,x+1/2x+6 + 2x+3/x^2+3x d,3/2x+6-x-6/2x^2+6x tính giúp mình vs ạ tks gấp

Toán Lớp 8: c,x+1/2x+6 + 2x+3/x^2+3x
d,3/2x+6-x-6/2x^2+6x
tính giúp mình vs ạ tks gấp

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    c)
    {x + 1}/{2x + 6} + {2x + 3}/{x^2 + 3x}
    = {x + 1}/{2(x + 3)}+ {2x + 3}/{x(x + 3)}
    = {x(x + 1)}/{2x(x + 3)}+ {2(2x + 3)}/{2x(x + 3)}
    = {x^2 + x}/{2x(x + 3)}+ {4x + 6}/{2x(x + 3)}
    = {x^2 + x + 4x + 6}/{2x(x + 3)}
    = {x^2 + 5x + 6}/{2x(x + 3)}
    = {x^2 + 3x + 2x + 6}/{2x(x + 3)}
    = {(x^2 + 3x) + (2x + 6) }/{2x(x + 3)}
    = {x(x + 3) + 2(x + 3)}/{2x(x + 3)}
    = {(x + 3)(x + 2)}/{2x(x + 3)}
    = {x + 2}/{2x}
    d)
    3/{2x + 6} – {x – 6}/{2x^2 + 6x}
    = 3/{2x + 6} – {x – 6}/{x(2x + 6)}
    = {3x}/{x(2x + 6)}- {x – 6}/{x(2x + 6)}
    = {3x – (x – 6)}/{x(2x + 6)}
    = {3x – x + 6}/{x(2x + 6)}
    = {2x + 6}/{x(2x + 6)}
    = 1/x
    #SunHee

  2. Giải đáp:
    c) $\frac{x+2}{2x}$
    d) $\frac{1}{x}$
    Lời giải và giải thích chi tiết:
    c) $\frac{x+1}{2x+6}+\frac{\:2x+3}{x^2+3x}$
    $=\frac{\left(x+1\right)x}{2x\left(x+3\right)}+\frac{\left(2x+3\right)\cdot \:2}{2x\left(x+3\right)}$
    $=\frac{\left(x+1\right)x+\left(2x+3\right)\cdot \:2}{2x\left(x+3\right)}$
    $=\frac{x^2+5x+6}{2x\left(x+3\right)}$
    $=\frac{x+2}{2x}$
    d) $\frac{3}{2x+6}-\frac{x-6}{2x^2+6x}$
    $=\frac{3x}{2x\left(x+3\right)}-\frac{x-6}{2x\left(x+3\right)}$
    $=\frac{3x-\left(x-6\right)}{2x\left(x+3\right)}$
    $=\frac{2x+6}{2x\left(x+3\right)}$
    $=\frac{1}{x}$
     

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

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