Câu 1:
\(a,\dfrac{x}{15}+\dfrac{7}{20}=\dfrac{73}{60}\)
\(\Rightarrow\dfrac{x}{15}=\dfrac{73}{60}-\dfrac{7}{20}\)
\(\Rightarrow\dfrac{x}{15}=\dfrac{13}{15}\)
\(\Rightarrow x=13\)
b, \(x+\dfrac{1}{3}=\dfrac{12}{20}\)
\(\Rightarrow x=\dfrac{3}{5}-\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{4}{15}\)
c, \(\dfrac{11}{8}+\dfrac{13}{6}=\dfrac{85}{x}\)
\(\Rightarrow\dfrac{85}{24}=\dfrac{85}{x}\)
\(\Rightarrow x=24\)
Câu 2:
a, \(60\%\cdot x+\dfrac{2}{3}\cdot x=-76\)
\(\Rightarrow x\cdot\left(60\%+\dfrac{2}{3}\right)=-76\)
\(\Rightarrow x\cdot\dfrac{19}{15}=-76\)
\(\Rightarrow x=-76:\dfrac{19}{15}\)
\(\Rightarrow x=-60\)
b, \(-\dfrac{5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
\(\Rightarrow-\dfrac{5}{6}-x=\dfrac{1}{4}\)
\(\Rightarrow x=-\dfrac{5}{6}-\dfrac{1}{4}\)
\(\Rightarrow x=-\dfrac{13}{12}\)
c, \(x-4=\dfrac{-14}{35}:\dfrac{7}{5}\)
\(\Rightarrow x-4=\dfrac{-2}{5}\cdot\dfrac{5}{7}\)
\(\Rightarrow x-4=-\dfrac{2}{7}\)
\(\Rightarrow x=-\dfrac{2}{7}+4\)
\(\Rightarrow x=\dfrac{26}{7}\)
d, \(\left(\dfrac{2}{7}\cdot x+\dfrac{3}{7}\right):\dfrac{11}{5}-\dfrac{3}{7}=1\)
\(\Rightarrow\left(\dfrac{2}{7}\cdot x+\dfrac{3}{7}\right)\cdot\dfrac{5}{11}=1+\dfrac{3}{7}\)
\(\Rightarrow\dfrac{2}{7}\cdot x\cdot\dfrac{5}{11}+\dfrac{3}{7}\cdot\dfrac{5}{11}=\dfrac{10}{7}\)
\(\Rightarrow\dfrac{10}{77}\cdot x+\dfrac{15}{77}=\dfrac{10}{7}\)
\(\Rightarrow\dfrac{10}{77}\cdot x=\dfrac{110}{77}-\dfrac{15}{77}\)
\(\Rightarrow\dfrac{10x}{77}=\dfrac{95}{77}\)
\(\Rightarrow10x=95\)
\(\Rightarrow x=95:10\)
\(\Rightarrow x=\dfrac{19}{2}\)
$\text{#}Toru$
`1a)x/15+7/20=73/60`
`=>x/15=73/60-7/20`
`=>x/15=13/15`
`=>x=13`
Vậy `x=13`
_
`b)x+1/3=12/20`
`=>x=12/20-1/3`
`=>x=4/5`
Vậy `x=4/5`
_
`c)11/8+13/6=85/x`
`=>85/24=85/x`
`=>x=24`
Vậy `x=24`
_
`2a)60%x+2/3x=-7/6`
`=>3/5x+2/3x=-7/6`
`=>19/15x=-7/6`
`=>x=-7/6:19/15`
`=>x=-105/114`
Vậy `x=-105/114`
_
`b)-5/6-x=7/12+(-1/3)`
`=>-5/6-x=1/4`
`=>x=-5/6-1/4`
`=>x=-13/12`
Vậy `x=-13/12`
_
`c)x-4=-14/35:7/5`
`=>x-4=-2/7`
`=>x=-2/7+4`
`=>x=26/7`
Vậy `x=26/7`
_
`d)(2/7x+3/7):11/5-3/7=1`
`=>(2/7x+3/7):11/5=3/7`
`=>2/7x+3/7=3/7 . 11/5`
`=>2/7x=3/7 . 11/5-3/7`
`=>2/7x=3/7(11/5-1)`
`=>2/7x=3/7 . 6/5`
`=>2/7x=18/35`
`=>x=18/35:2/7`
`=>x=9/5`
