a) 2x– 3 = 3(x – 1) + x + 2 ; b) 2x(x –3) – 5(x –3) = 0
c)
2
2xxx8
x1(x1)(x4)
giả hộ mình vs mình vote cho 5 sao nhố
a) 2x– 3 = 3(x – 1) + x + 2 ; b) 2x(x –3) – 5(x –3) = 0 c) 2 2xxx8 x1(x1)(x4) giả hộ mình vs mình vote cho 5 sao nhố
By Lyla
a, 2x– 3 = 3(x – 1)+x+2
⇔2x-3=3x-3+x+2
⇔2x-3=4x-1
⇔2x-4x=3-1
⇔-2x =2
⇔x=-1
b,2x(x –3) – 5(x –3)=0
⇔2x²-6x-5x+15 =0
⇔2x²-11x+15 =0
⇔(2x²-6x)-(5x-15) =0
⇔2x(x-3)-4(x-3) =0
⇔(x-3)(2x-4) =0
⇔\(\left[ \begin{array}{l}x-3=0\\2x-4=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=3\\x=2\end{array} \right.\)
c, đkxđ:x$\neq$1;-4
$\frac{2x}{x+1}$ =$\frac{x²-x+8}{(x-1)(x+4)}$
⇔$\frac{2x(x+4)}{(x+1)(x-1)}$ =$\frac{x²-x+8}{(x-1)(x+4)}$
⇔2x(x+4)=x²-x+8
⇔2x²+8x=x²-x+8
⇔2x²+8x-x²+x-8=0
⇔(x²+x)-(8x+8)=0
⇔x(x+1)-8(x+1)=0
⇔(x+1)(x-8)=0
⇔\(\left[ \begin{array}{l}x+1=0\\x-8=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-1\\x=8\end{array} \right.\)
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