1)

a)

\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)

\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)

\(\frac{-20}{5}< x< \frac{-3}{10}\)

\(\frac{-40}{10}< x< \frac{-3}{10}\)

\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)

\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)

\(\frac{25}{3}< x< \frac{-4}{7}.\frac{1}{1}\)

\(\frac{-25}{3}< x< \frac{-4}{7}\)

\(\frac{-175}{21}< x< \frac{-12}{21}\)

\(\Rightarrow Z\in\left\{-13;-14;-15;-16;...;-174\right\}\)

Ta có : \(\frac{3}{2x+1}+\frac{10}{4x+2}-\frac{6}{6x+3}=\frac{12}{26}\)

\(\Rightarrow\frac{3}{2x+1}+\frac{5.2}{2\left(2x+1\right)}-\frac{3.2}{3\left(2x+1\right)}=\frac{6}{13}\)

=> \(\frac{3}{2x+1}+\frac{5}{2x+1}-\frac{2}{2x+1}=\frac{6}{13}\)

=> \(\frac{3+5-2}{2x+1}=\frac{6}{13}\)

=> \(\frac{6}{2x+1}=\frac{6}{13}\)

=> 2x + 1 = 13

=> 2x = 12

=> x = 6

Vậy x = 6

\(\frac{3}{2x+1}+\frac{10}{2\left(2x+1\right)}-\frac{6}{3\left(2x+1\right)}=\frac{6}{13}\)                

\(\frac{3}{2x+1}+\frac{5}{2x+1}-\frac{2}{2x+1}=\frac{6}{13}\)                

\(\frac{6}{2x+1}=\frac{6}{13}\)  

\(\Rightarrow2x+1=13\left(6=6\right)\)         

\(2x=12\)    

\(x=6\)     

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a} đây là biểu thức gì\)

a) =-5/7 +7/8-2/7+1/8- -1/12+ -13/12

=(-5/7-2/7)+(7/8+1/8)-(-1/12--13/12)

=-7/7+8/8 - 12/12

= -1+1+1

=1

b)= ( -3/8+11/8)-(12/11+ -1/11)+(-3/5- 2/5)

= 1- 1 + (-1)

=-1

dễ lắm ó

a) \(\frac{2}{3}\left(\frac{1}{2}+\frac{3}{4}-\frac{1}{3}\right)\le\frac{x}{18}\)

\(\frac{x}{18}\le\frac{7}{3}\left(\frac{1}{2}-\frac{1}{6}\right)\)

tu tim x o 2 truong hop tren
b) de \(\frac{11}{2x+1}\) nguyen thi \(2x+1\inƯ\left(11\right)=\left\{\pm1;\pm11\right\}\)

2x+1=-1 suy ra x=-1

2x+1=1 suy ra x=0

2x+1=11 suy ra x=5

2x+1=-11 suy ra x=-6

Vay de ......thi x thuoc {-1;0;5;6}

cảm ơn bạn