x=0

x=-3

(x+1)(x+2) = 2

x² + 2x + x + 2 = 2

            x² + 3x = 2 - 2

           x(x + 3) = 2

⇒ x = 0 hoặc x + 3 = 0

⇒ x = 0 hoặc x = -3

Vậy tập nghiệm S = {-3}

m=1

`hpt`:$\begin{cases}x+y=1\\x+4y=2\\\end{cases}$

`<=>` $\begin{cases}3y=1\\x=1-y\\\end{cases}$

`<=>` $\begin{cases}y=\dfrac13\\x=\dfrac23\\\end{cases}$

⇔m2x−mx−2x+m−2=0

⇔m2x−4x−mx+2x+m−2=0

⇔x(m−2)(m+2)−x(m−2)+(m−2)=0

⇔(mx+2x−x+1)(m−2)=0

⇔((m+1)x+1)(m−2)=0

⇒[x=−1m+1  m=2thì TM mọi x thuôộc R

     m=2

e mới vào lớp 6 chị ơi

a/ PT <=> (x² - 6x + 9) + (x - \(\sqrt{3x}\)) + (3 - \(\sqrt{3x}\)) = 0

<=> (\(\sqrt{x}-\sqrt{3}\))(\(\sqrt{3}x+x\sqrt{x}-3\sqrt{x}-3\sqrt{3}\)) + √x(\(\sqrt{x}-\sqrt{3}\)) + \(\sqrt{3}\left(\sqrt{3}-\sqrt{x}\right)\)= 0

<=> x = 3

b/ bình phương 2 vế ta có

x⁴ - 8³ + 16x² - 64x + 64 = 0

<=> (x² + 8)(x² - 8x + 8) = 0

<=> x = \(4\:+\:2\sqrt{2}\)

1) \(\frac{4x-8}{2x^2+1}=0\)

<=> \(\frac{4\left(x-2\right)}{2x^2+1}=0\)

<=> 4(x - 2) = 0

<=> x - 2 = 0

<=> x = 2

2) \(\frac{x^2-x-6}{x-3}=0\)

<=> \(\frac{\left(x+2\right)\left(x-3\right)}{x-3}=0\)

<=> x + 2 = 0

<=> x = -2

3) xem ở đây Câu hỏi của Vương Thanh Thanh

4) \(\frac{12}{1-9x^2}=\frac{1-3x}{1+3x}-\frac{1+3x}{1-3x}\)

<=> \(\frac{12}{\left(1+3x\right)\left(1-3x\right)}=\frac{1-3x}{1+3x}-\frac{1+3x}{1-3x}\)

<=> 12 = (1 - 3x)² - (1 + 3x²)

<=> 12 = 1 - 6x + 9x² - 1 - 6x - 9x²

<=> 12 = -12x

<=> x = -1

5) ĐKXĐ: \(x\ne1,x\ne3\)

\(\frac{x+5}{x-1}=\frac{x+1}{x-3}-\frac{8}{x^2-4x+3}\)

<=> \(\frac{x+5}{x-1}=\frac{x+1}{x-3}-\frac{8}{\left(x-1\right)\left(x-3\right)}\)

<=> (x + 5)(x - 3) = (x + 1)(x - 1) - 8

<=> x² - 3x + 5x - 15 = x² - x + x - 1 - 8

<=> x² + 2x - 15 = x² - 9

<=> x² + 2x - 15 - x² = -9

<=> 2x - 15 = -9

<=> 2x = -9 + 15

<=> 2x = 6

<=> x = 3 (ktm)

=> pt vô nghiệm

6) ĐKXĐ: \(x\ne\pm2\)

\(\frac{x+1}{x-2}-\frac{5}{x+2}=\frac{12}{x^2-4}+1\)

<=> \(\frac{x+1}{x-2}-\frac{5}{x+2}=\frac{12}{\left(x-2\right)\left(x+2\right)}+1\)

<=> (x + 1)(x + 2) - 5(x - 2) = 12 + (x - 2)(x + 2)

<=> x² + 2x + x + 2 - 5x + 10 = 12 + x² + 2x - 2x - 4

<=> x² - 2x + 12 = x² + 8

<=> x² - 2x + 12 - x² = 8

<=> -2x + 12 = 8

<=> -2x = 8 - 12

<=> -2x = -4

<=> x = 2 (ktm)

=> pt vô nghiệm

X = - 1000/507

\(\dfrac{x}{40}-\dfrac{x+4}{52}=2\)

\(\Rightarrow52x-40x-160=4160\Leftrightarrow12x=4320\Leftrightarrow x=360\)