\(\dfrac{0.375-0.3+\dfrac{3}{11}+\dfrac{3}{12}}{-0.625+0.5-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{1.5+1-0.75}{2.5+\dfrac{5}{3}-1.25}\)

=\(\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}\)

=\(\dfrac{3.\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}{-5.\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}+\dfrac{3\cdot\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}{5\cdot\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}\)

=\(\dfrac{3}{-5}+\dfrac{3}{5}\)

=\(0\)

\(A=\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}\\ A=\dfrac{3\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}{-5\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}+\dfrac{3\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}{5\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}\\ A=\dfrac{-3}{5}+\dfrac{3}{5}=0\)

\(A=\dfrac{0,375-0,3+\dfrac{3}{11}+\dfrac{3}{12}}{-0,625+0,5-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{1,5+1-0,75}{2,5+\dfrac{5}{3}-1,25}=\dfrac{3\left(0,125-0,1+\dfrac{1}{11}+\dfrac{1}{12}\right)}{-5\left(0,125-0,1+\dfrac{5}{11}+\dfrac{5}{12}\right)}+\dfrac{\dfrac{3}{5}\left(2,5+\dfrac{5}{3}-1,25\right)}{2,5+\dfrac{5}{3}-1,25}=-\dfrac{3}{5}+\dfrac{3}{5}=0\)

xem lại đề 0,625 hay 0.265

Bạn có thể xem lại đề ko?

a\()\)1/2-1/2:x=3/4

1/2:x=3/4+1/2

1/2:x=5/4

x=5/4*1/2

x=5/8

a,1/2:x=-1/4

x=1/2:-1/4

x=-2

b,Coi 3/5=-3/-5

x=-3+1=-2

c,x=-1,1

\(=\left(\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}+\dfrac{3\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}{-5\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}\right)\cdot\dfrac{2005}{1890}+115\)

\(=\left(\dfrac{3}{5}-\dfrac{3}{5}\right)\cdot\dfrac{2005}{1890}+115\)

=115

\(=\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}\)

\(=\dfrac{-3}{5}+\dfrac{3}{5}=0\)

\(\left(x+2,5\right):2\dfrac{1}{2}-1,5=-1\dfrac{1}{4}\\ < =>\left(x+\dfrac{5}{2}\right):\dfrac{5}{2}-\dfrac{3}{2}=-\dfrac{5}{4}\\ =>\left(x+\dfrac{5}{2}\right).\dfrac{2}{5}=-\dfrac{5}{4}+\dfrac{3}{2}=\dfrac{1}{4}\\ =>x+\dfrac{5}{2}=\dfrac{1}{4}:\dfrac{2}{5}=\dfrac{5}{8}\\ =>x=\dfrac{5}{8}-\dfrac{5}{2}=-\dfrac{15}{8}\)

\(\left(x+2,5\right):2\dfrac{1}{2}-1,5=-1\dfrac{1}{4}\)

\(\Leftrightarrow\left(x+\dfrac{5}{2}\right):\dfrac{5}{2}-\dfrac{3}{2}=\dfrac{-5}{4}\)

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

\(\left(x+\dfrac{5}{2}\right):\dfrac{5}{2}=\dfrac{1}{4}\)

\(x+\dfrac{5}{2}=\dfrac{1}{4}.\dfrac{5}{2}\)

\(x+\dfrac{5}{2}=\dfrac{5}{8}\)

\(x=\dfrac{5}{8}-\dfrac{5}{2}\)

\(x=\dfrac{-15}{8}\)

Vậy \(x=\dfrac{-15}{8}\)

\(D=\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{\dfrac{-5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}\)

\(=\dfrac{-3}{5}+\dfrac{3}{5}=0\)

a) Ta có: |x- 1,5| + |2,5-x| =0

=>x-1,5=0 và 2,5 - x =0

=> x = 1,5 và x = 2,5

Vậy x thuộc {1,5; 2,5}

Còn câu b mik hk bt lm

phần b cậu vào câu hỏi của tớ mà xem

\(\left|x-1,5\right|+\left|2,5-x\right|\ge\left|x-1,5+2,5-x\right|=1>0\)

Không có giá trị \(x\) thỏa mãn

\(\dfrac{x+1}{9}+\dfrac{x+1}{8}=\dfrac{x+1}{11}+\dfrac{x+1}{12}\)

\(\Rightarrow\dfrac{x+1}{9}+\dfrac{x+1}{8}-\dfrac{x+1}{11}-\dfrac{x+1}{12}=0\)

\(\Rightarrow\left(x+1\right)\left(\dfrac{1}{9}+\dfrac{1}{8}-\dfrac{1}{11}-\dfrac{1}{12}\right)=0\)

Vì \(\dfrac{1}{9}+\dfrac{1}{8}-\dfrac{1}{11}-\dfrac{1}{12}\ne0\Leftrightarrow x=-1\)