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

Toán Lớp 8: Rút gọn phân thức: $a)\frac{5x^{4}-5x}{2x^{3}-4x^{2}+2x}$ $b)\frac{3x^{4}+18x^{3}+27x^{2}}{x^{3}+5x^{2}+6x}$

Tháng Mười 24, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Rút gọn phân thức:
$a)\frac{5x^{4}-5x}{2x^{3}-4x^{2}+2x}$
$b)\frac{3x^{4}+18x^{3}+27x^{2}}{x^{3}+5x^{2}+6x}$

Comments ( 2 )

  1. cobexinhdep
    cobexinhdep
    24 Tháng Mười, 2022 at 11:50 sáng
    Reply
    a) $\frac{5x_{4}-5x }{2x³-4x²+2x}$
    = $\frac{5x(x³-1)}{2x(x²-2x+1)}$ 
    = $\frac{5x(x³-1)}{2x(x-1)²}$ 
    = $\frac{5x(x-1)(x²+x+1)}{2x(x-1)²}$ 
    = $\frac{5(x²+x+1)}{2(x-1)}$
    b) $\frac{3x_{4}+18x³+27x²}{x³+5x²+6x}$
    = $\frac{3x²(x²+6x+9}{x³+6x²-x²+6x}$
    = $\frac{3x²(x+3)²}{x³+3x²+2x²+6x}$ 
    = $\frac{3x²(x+3)²}{x²(x+3)+2x(x+3)}$ 
    = $\frac{3x²(x+3)²}{(x+3)(x²+2x)}$ 
    = $\frac{3x²(x+3)²}{x(x+3)(x+2)}$
    = $\frac{3x²(x+3)}{x(x+2)}$  
    = $\frac{3x(x+3)}{(x+2)}$  

  2. buithaianh98
    buithaianh98
    24 Tháng Mười, 2022 at 11:50 sáng
    Reply
    ${ a) \dfrac{5x^4 – 5x}{2x^3 – 4x^2 + 2x} }$
    ${ = \dfrac{5x. (x^3 – 1)}{2x. (x^2 – 2x + 1)} }$
    ${ = \dfrac{5x. (x – 1). (x^2 – x + 1)}{2x. (x – 1)^2} }$
    ${ = \dfrac{5. (x^2 – x + 1)}{2. (x – 1)} }$
    ${ b) \dfrac{3x^4 +18x^3 + 27x^2}{x^3 + 5x^2 + 6x} }$
    ${ = \dfrac{3x^2. (x^2 + 6x + 9)}{x^3 + 2x^2 + 3x^2 + 6x} }$
    ${ = \dfrac{3x^2. (x + 3)^2}{x^2. (x + 2) + 3x. (x + 2)} }$
    ${ = \dfrac{3x^2. (x + 3)^2}{x. (x + 3). (x + 2)} }$
    ${ = \dfrac{3x. (x + 3)}{x + 2} }$
     

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

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