\(\dfrac{6x+5}{5x-3}=\dfrac{38-6x}{21-5x}\left(đk:x\ne\dfrac{5}{3},x\ne\dfrac{21}{5}\right)\)

\(\Rightarrow\left(6x+5\right)\left(21-5x\right)=\left(5x-3\right)\left(38-6x\right)\)

\(\Rightarrow-30x^2+101x+105=-30x^2+208x-114\)

\(\Rightarrow107x=219\Rightarrow x=\dfrac{219}{107}\left(tm\right)\)

\(\dfrac{6x+5}{5x-3}=\dfrac{6x-38}{5x-21}\)

\(\Leftrightarrow30x^2-126x+25x-105=30x^2-18x-190x+114\)

\(\Leftrightarrow-101x-105=-208x+114\)

\(\Leftrightarrow107x=219\)

hay \(x=\dfrac{219}{107}\)

Ta có : 

\(\left(1-6x\right)^2+2\left(6x-1\right)\left(2-5x\right)+\left(2-5x\right)^2\)

\(=\)\(\left(6x-1\right)^2+2\left(6x-1\right)\left(2-5x\right)+\left(2-5x\right)^2\)

\(=\)\(\left(6x-1+2-5x\right)^2\)

\(=\)\(\left(x+1\right)^2\)

Bài này thiếu Vế Phải nha bạn 

Chúc bạn học tốt ~ 

\(\Leftrightarrow6x+4-5\left|x\right|=16\\ \Leftrightarrow5\left|x\right|=6x-12\\ \Leftrightarrow\left[{}\begin{matrix}5x=6x-12\left(x\ge0\right)\\5x=12-6x\left(x< 0\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=12\left(tm\right)\\x=\dfrac{12}{11}\left(ktm\right)\end{matrix}\right.\)

5x(2-3x)=4-6x

<=>10x-15x²=4-6x

<=>10x+6x-4-15x²=0

<=>-15x²+16x-4=0

<=>-15(x²-16/15.x+4/15)=0

<=>x²-2/5.x-2/3.x+4/15=0

<=>x(x-2/5)-2/3.(x-2/5)=0

<=>(x-2/3)(x-2/5)=0

<=> x-2/3=0 hoặc x-2/5=0

<=>x=2/3 hoặc x=2/5

5x.(2-3.x)=4-6x

5x(2-3x)=2(2-3x)

5x(2-3x)-2(2-3x)=0

(2-3x)(5x-2)=0

=>2-3x=0 hoặc 5x-2=0

     -3x =-2 hoặc 5x=2

       x =2/3 hoặc x=2/5

Vậy x=2/3;2/5

\(6x-4+5x-3+4-10=9\)

\(6x+5x+4x=9+4+3+10\)

\(15x=26\)

\(x=\dfrac{26}{15}\)

\(6x-4+5x-3+4x-10-9=0\)

\(15x-26=0\)

\(x=\dfrac{26}{15}\)

\((x-2)^3-(x+5)(x^2-5x+25)+6x^2=11\\\Leftrightarrow (x-2)^3-(x+5)(x^2-5.x+5^2)+6x^2=11 \\\Leftrightarrow x^3-6x^2+12x-8 -(x^3+5^3)+6x^2-11=0 \\\Leftrightarrow 12x-144=0 \\\Leftrightarrow x=12\)

Vậy \(x=12\).

(x−2)3−(x+5)(x2−5x+25)+6x2=11

=>(x−2)3−(x+5)(x2−5.x+52)+6x2=11

=>x3−6x2+12x−8−(x3+53)+6x2−11=0

=>12x−144=0

=>x=12(x−2)3−(x+5)(x2−5x+25)+6x2=11

=>(x−2)3−(x+5)(x2−5.x+52)+6x2=11

=>x3−6x2+12x−8−(x3+53)+6x2−11=0

=>12x−144=0

=>x=12

Vậy x=12x=12.

cho tôi đúng đi

(5x+75)(12-6x)=0

=> 5x+75=0 hoặc 12-6x=0

* 5x+75=0=>x=-15

*12-6x=0=>x=2

Vậy x=-15 hoặc x=2

PT <=> (3x - 1)(6x - 1)(4x - 1)(5x - 1) = 120 
. <=> (18x² - 9x + 1)(20x² - 9x + 1) = 120 
Đặt a = 19x² - 9x + 1 (Đk a > 0) ta có PT: (a - 1)(a + 1) = 120 
<=> a² - 1 = 120 
<=> a² = 121 
<=> a = 11 (Vì a >0) 
Với a = 11 ta có PT: 19x² - 9x - 10 = 0 
<=> (10x + 19)(x - 1) = 0 
<=> x = 1 (Vì x nguyên) 
KL: x = 1