\(2(x-5)-3(x+6)=10+x\)

\(\Rightarrow2x-10-3x+18=10x\)

\(\Rightarrow2x-10-3x-18=10+x\)

\(\Rightarrow-x-28=10+x\)

\(\Rightarrow-x-x=10+28\)

\(\Rightarrow-2x=38\)

\(\Rightarrow x=-19\)

Vậy ..

\(2\left(x-5\right)-\left(3x+6\right)=10+x\)

\(\Rightarrow2x-10-3x-18=10+x\)

\(\Rightarrow-x-28=10+x\)

\(\Rightarrow-x=38+x\)

\(\Rightarrow-2x=38\Leftrightarrow x=-19\)

số 14 nha bạn ~~~

mình không biết cách làm, nhưng mình biết x = 7,5

\(4x-3-x-5-=x+2-2x+2.10\)

\(3x-8=x+2-2x+20\)

\(3x=x+10-2x+20\)

\(3x=-x+30\)

\(4x=30\)

\(x=\frac{30}{4}=7,5\)

Cam on cac b mk cx ra ket qua la 7,5

a) \(\Leftrightarrow\left|2x-3\right|=\frac{1}{4}\Leftrightarrow\orbr{\begin{cases}x\ge\frac{3}{2}\mid:2x-3=\frac{1}{4}\Rightarrow2x=\frac{13}{4}\Rightarrow x=\frac{13}{8}\left(TM\right)\\x< \frac{3}{2}\mid:3-2x=\frac{1}{4}\Rightarrow2x=\frac{11}{4}\Rightarrow x=\frac{11}{8}\left(TM\right)\end{cases}.}\)

b) \(\Leftrightarrow\left|x-1\right|=\frac{3}{4}\Leftrightarrow\orbr{\begin{cases}x\ge1\mid:x-1=\frac{3}{4}\Rightarrow x=\frac{7}{4}\left(TM\right)\\x< 1\mid:1-x=\frac{3}{4}=>x=\frac{1}{4}\left(TM\right)\end{cases}}\)

c) \(\frac{3}{5\left(x-\frac{5}{6}\right)}-\frac{1}{2\left(\frac{3}{2}-1\right)}=-\frac{1}{4}\Leftrightarrow\frac{3}{\frac{5\left(6x-5\right)}{6}}-\frac{1}{2\cdot\frac{1}{2}}=-\frac{1}{4}\Leftrightarrow\frac{18}{5\left(6x-5\right)}=-\frac{1}{4}+1\)

\(\Leftrightarrow\frac{18}{5\left(6x-5\right)}=\frac{3}{4}\Leftrightarrow6x-5=\frac{24}{5}\Leftrightarrow6x=\frac{49}{5}\Leftrightarrow x=\frac{49}{30}\)

d) \(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2015}{2016}\)

\(\Leftrightarrow\frac{2}{2\cdot3}+\frac{2}{3\cdot4}+\frac{2}{4\cdot5}+...+\frac{2}{x\left(x+1\right)}=\frac{2015}{2016}\)

\(\Leftrightarrow2\cdot\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}\right)=\frac{2015}{2016}\)

\(\Leftrightarrow2\left(\frac{1}{2}-\frac{1}{x+1}\right)=\frac{2015}{2016}\Leftrightarrow2\cdot\frac{x+1-2}{2\left(x+1\right)}=\frac{2015}{2016}\Leftrightarrow\frac{x-1}{x+1}=\frac{2015}{2016}\)

\(\Leftrightarrow2016x-2016=2015x+2015\Leftrightarrow x=2015+2016=4031\)

Vậy x = 4031.

a)   6 + 2x = 12 +(-5)

     2x = 7 -6

    x = 1/2

b)  -90 - |x| -10 + 100 = 0

            - |x| =0

               x =0