(2 + 5)x(3-1)+27:(18-5)-6

=7 * 2 + 27 : 13 - 6

=14 + 27 : 13 - 6

=14 + 27/13 - 6

=209/13

=131/13

(2+5)x(3-1)+27:(18-5)-6

=7x2+27:13-6

=14+27:13-6

=14+27/13:6

=209/13

=131/13

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

\(\Rightarrow\frac{2}{3}x-\frac{1}{2}x=\frac{5}{4}\)

\(\frac{1}{6}x=\frac{5}{4}\)

\(x=\frac{5}{4}:\frac{1}{6}\)

x = 15/2

2/3.x = 5/4 + 1/2 . x

2/3. x - 1/2 . x =5/4

(2/3-1/2).x=5/4

1/3.x=5/4

x=5/4:1/3

x=15/4

\(|x|-\frac{3}{4}=\frac{5}{3}\)

\(\left|x\right|=\frac{5}{3}-\frac{3}{4}\)

\(\left|x\right|=\frac{20}{12}-\frac{9}{12}\)

\(\left|x\right|=\frac{11}{12}\)

\(\Rightarrow\orbr{\begin{cases}\left|x\right|=\frac{11}{12}\\\left|x\right|=\frac{-11}{12}\end{cases}}\)

\(|x|-\frac{3}{4}=\frac{5}{3}\)

\(|x|=\frac{5}{3}+\frac{3}{4}\)

\(|x|=\frac{20}{12}+\frac{9}{12}\)

\(|x|=\frac{29}{12}\)

\(\Rightarrow x=\frac{29}{12}\)hoặc \(x=\frac{-29}{12}\)

Làm như zậy bạn nhé ^_^"

Đặt :

\(A=\left(\frac{1}{1}.\frac{1}{2}+\frac{1}{2}.\frac{1}{3}+\frac{1}{3}.\frac{1}{4}+\frac{1}{4}.\frac{1}{5}+\frac{1}{5}.\frac{1}{6}\right)\)

\(A=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{5.6}\)( mik lười viết bạn thông cảm nhé !!! )

\(A=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{5}-\frac{1}{6}\)

\(A=\frac{1}{1}-\frac{1}{6}\)

\(A=\frac{5}{6}\)

Thay A vào biểu thức :

Ta có : \(\frac{5}{6}.10-x=0\)

=> \(\frac{25}{3}=x+0\)

=> \(x=\frac{25}{3}\)

(1/1*1/2+1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6)*10-x=0

=> (1/1.2+1/2.3+1/3.4+1/4.5+1/5.6)*10-x=0

=> (1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)*10-x=0

=> (1-1/6)*10-x=0

=> 5/6*10-x=0

=> 25/3-x =0

=> x=0+25/3

=> x=25/3

Vậy x=25/3

là 1 Số nguyên âm !

là kết quả 

45-(5-2x)^2=4375

-(5-2x)^2=45-4375

-(10-4x)=-4330

-10+4x=-4330

4x=-4330+10

4x=-4320

x=-1080

\(\frac{1}{3}\) + \(\frac{5}{6}\): \(\left(x-2\frac{1}{5}\right)\)= \(\frac{3}{4}\)

<=> \(\frac{5}{6}\):\(\left(x-2\frac{1}{5}\right)\)= \(\frac{3}{4}\)- \(\frac{1}{3}\)

<=> \(\frac{5}{6}\) : \(\left(x-2\frac{1}{5}\right)\) = \(\frac{5}{12}\)

<=> \(\left(x-2\frac{1}{5}\right)\) =    \(\frac{5}{6}\) : \(\frac{5}{12}\)

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

<=. x = 2 + \(\frac{11}{5}\)

<=> x = \(\frac{21}{5}\)

\(-\frac{2}{3}x+\frac{1}{5}=\frac{1}{3}\times\left(\frac{-1}{6}\right)\)

\(-\frac{2}{3}x+\frac{1}{5}=-\frac{1}{18}\)

\(-\frac{2}{3}x=-\frac{1}{18}-\frac{1}{5}\)

\(\frac{-2}{3}x=\frac{-5}{90}-\frac{18}{90}=-\frac{23}{90}\)

\(x=-\frac{23}{90}:\frac{-2}{3}\)

\(x=-\frac{23}{90}.\frac{3}{-2}=\frac{23}{60}\)

Vậy \(x=\frac{23}{60}\)

1/2+1/3+14

= 5/6 + 14

= 89/6

Chúc bạn học tốt nhé! ^-^

=5/6+14

=89/6

89/6 nha