Đáp án:
Giải thích các bước giải:
`a, x= \frac{7}{25} +\frac{-1}{5}`
`=> x=\frac{7}{25} -1/5`
`=> x=\frac{7}{25} - \frac{5}{25}`
`=> x=\frac{2}{25}`
`b, x=\frac{5}{11}+\frac{4}{-9}`
`=> x=\frac{5}{11} -4/9`
`=> x=\frac{45}{99} -\frac{44}{99}`
`=> x=\frac{1}{99}`
`c, 5/9 +x =-1/3`
`=> x=-1/3 -5/9`
`=> x =- 3/9 -5/9`
`=> x=-8/9`
`d, 2/3 +x =\frac{7}{14}`
`=> x=\frac{7}{14} -2/3`
`=> x=1/2 -2/3`
`=> x=3/6 -4/6`
`=> x=-1/6`
