\(\Leftrightarrow6x^2-14x+4-6x^2-12x+18-7x+3=0\)

\(\Leftrightarrow-33x=-25\Rightarrow x=\frac{25}{33}\)

2( 3x - 1 )( x - 2 ) - 6( x - 1 )( x + 3 ) = 7x - 3 

<=> 2( 3x² - 7x + 2 ) - 6( x² + 2x - 3 ) = 7x - 3

<=> 6x² - 14x + 4 - 6x² - 12x + 18 = 7x - 3

<=> -26x + 22 = 7x - 3

<=> -26x - 7x = -3 - 22

<=> -33x = -25

<=> x = 25/33

<=> -36x = 

dễ vậy mà không biết hả trời

7x+2/5x+7=7x-1/5x+1=>37/5x+7=34/5x+1=>37/5x-34/5x=1-7=>3/5x=-6=>x=-6:3/5=-10 vay x=-10 nho ****

em đang cần gấp các cao nhân ơi

(x-1)(2x^2-8)=0

\(\Leftrightarrow\left(x-1\right)\left(2x^2-8\right)=0\\ \left(2x^3-8x-2x^2+8\right)=0\)

\(\Leftrightarrow2x\left(x-1\right)-8\left(x-1\right)=0\)

\(\Leftrightarrow x=1;x=\dfrac{8}{2}\)

3x^2-8x+5=0

áp dụng công thức bậc 2 ta có:

\(x=\dfrac{-\left(-8\right)\pm\sqrt{\left(-8\right)^2-4.3.5}}{2.3}\)

\(\Rightarrow x=\dfrac{5}{3};x=1\)

(7x-1).2x-7x+1=0

\(\Leftrightarrow\left(7x-1\right)\left(2x-1\right)=0\)

\(\Leftrightarrow x=\dfrac{1}{7};x=\dfrac{1}{2}\)

ngu thế à bạn

               Để olm giúp em em nhé!

a,   \(\dfrac{x+2}{7x+42}\) = \(\dfrac{x+2}{7.\left(x+6\right)}\) = \(\dfrac{\left(x+2\right)\left(x-6\right)}{7\left(x-6\right)\left(x+6\right)}\) (đk \(x\ne\) \(\mp\) 6)

 \(\dfrac{-13x}{x^2-36}\) = \(\dfrac{-13x}{\left(x-6\right)\left(x+6\right)}\) = \(\dfrac{-7.13.x}{7.\left(x-6\right).\left(x+6\right)}\) = \(\dfrac{-91x}{7.\left(x-6\right)\left(x+6\right)}\)

b, \(\dfrac{7}{4x+16}\) = \(\dfrac{7\left(x-4\right)}{4.\left(x+4\right).\left(x-4\right)}\) (đk \(x\ne\) \(\pm\) 4)

     \(\dfrac{15}{x^2-16}\) = \(\dfrac{15.4}{\left(x-4\right)\left(x+4\right).4}\) = \(\dfrac{60}{4.\left(x-4\right).\left(x+4\right)}\)

a) \(\Leftrightarrow\left(-63x^2+78x-15\right)+\left(63x^3+x-20\right)=44\)

\(\Leftrightarrow-63x^2+78x-15+63x^2+x-20=44\)

\(\Leftrightarrow79x-35=44\)

\(\Leftrightarrow79x=44+35\)

\(\Leftrightarrow79x=79\)

\(\Leftrightarrow x=1\)

b) \(\Leftrightarrow\left(x^2+3x+2\right).\left(x+5\right)-x^2.\left(x+8\right)=27\)

\(\Leftrightarrow x.\left(x^2+3x+2\right)+5.\left(x^2+3x+2\right)-x^3-8x^2=27\)

\(\Leftrightarrow x^3+3x^2+2x+5x^2+15x+10-x^3-8x^2=27\)

\(\Leftrightarrow17x+10=27\)

\(\Leftrightarrow17x=17\)

\(\Leftrightarrow x=1\)

-7x + 3(x-1) > 8-x

-7x + 3x - 3 > 8-x

-4x - 3 > 8 - x

-4x + x > 8+3

-3x > 11

    x > -11/3

    -7x + 3(x -1)>8 - x
⇔ -7x + 3x - 3>8 - x
⇔ -7x + 3x + x> 8 + 3
⇔ -3x>11
⇔ x< -11/3