\(-\frac{15}{12}+x+\frac{3}{7}=\frac{6}{5}x-\frac{1}{2}\)

<=>\(x-\frac{6}{5}x=-\frac{1}{2}+\frac{15}{12}-\frac{3}{7}\)

<=>\(-\frac{1}{5}x=\frac{9}{28}\)

<=>\(x=\frac{9}{28}:\left(-\frac{1}{5}\right)\)

<=>\(x=-\frac{45}{28}\)

• a,  Do \(\left[3x-15\right]^7=0\)

                     =>    \(3x-15=0\) 

                     =>    \(3x=0+15\)

                     =>    \(3x=15\)

                     =>    \(x=15:3\)

                     =>    \(x=5\)

\(\left(3x-5\right)^7=0\)

\(\Rightarrow3x-5=0\)

\(\Rightarrow3x=5\)

\(\Rightarrow x=\frac{5}{3}\)

a) \(\dfrac{x}{15}\)=\(\dfrac{x-2}{30}\)

=>30x=15 (x-2)

=>30x=15x-30

=>30x-15x=-30

=>15x =-30

=>x =-2

b)\(\dfrac{7}{8}\)<\(\dfrac{x}{80}\)<\(\dfrac{9}{10}\)

=>\(\dfrac{70}{80}\)<\(\dfrac{x}{80}\)<\(\dfrac{72}{80}\)

=> 70<x<72

=>x=71

c)\(\dfrac{1}{6}\)<\(\dfrac{5}{x}\)<\(\dfrac{1}{4}\)

=>\(\dfrac{5}{30}\)<\(\dfrac{5}{x}\)<\(\dfrac{5}{20}\)

=>20<x<30

=>x={21;22;23;24;25;26;27;28;29}

a) x¹⁵ = x 

=> x¹⁵ - x = 0

=> x(x¹⁴ - 1) = 0

=> x = 0 

hoặc x¹⁴ - 1 = 0 => x¹⁴ = 1 => x = 1

=> x \(\in\){0;1}

bai nay de ma ban

\(\left(3x-15\right)\left(2x-6\right)=2x-6\) 

\(\Leftrightarrow\left(3x-15\right)\left(2x-6\right)-\left(2x-6\right)=0\)

\(\Leftrightarrow\left(2x-6\right)\left(3x-16\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}2x-6=0\\3x-16=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=\frac{16}{3}\end{cases}}\)

(3x-15).(2x-6)=2x-6

3x-15           =(2x-6):(2x-6)

3x-15           =1

3x                =1+15

3x                =16

  x                =16:3

  x                = 8

Vậy x =8