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![](https://rs.olm.vn/images/avt/0.png?1311)
a) |a| = a b) |a| > -a
c) |a-10| = a-10 d) |a-10| > 10-a
![](https://rs.olm.vn/images/avt/0.png?1311)
A} x - 8 / 2x - 17
x=8
B} x - 4 / x - 1
x=4
câu C mk không tính ra, mk chỉ giúp được 2 câu trên thôi
![](https://rs.olm.vn/images/avt/0.png?1311)
a. \(\frac{1}{5}+\frac{3}{4}+\frac{1}{10}\)
= \(\frac{4}{20}+\frac{15}{20}+\frac{2}{20}\)
= \(\frac{21}{20}\)
b. \(\frac{5}{6}-\frac{1}{3}+\frac{1}{6}\)
= \(\frac{5}{6}-\frac{2}{6}+\frac{1}{6}\)
= \(\frac{4}{6}=\frac{2}{3}\)
c. \(\frac{3}{8}-\frac{10}{2}:\frac{4}{5}\)
= \(\frac{3}{8}-\frac{50}{8}\)
= \(\frac{-47}{8}\)
a) \(\frac{1}{5}+\frac{3}{4}+\frac{1}{10}\)
= \(\frac{4+15+2}{20}\)
= \(\frac{21}{20}\)
b) \(\frac{5}{6}-\frac{1}{3}+\frac{1}{6}\)
= \(\frac{5-2+1}{6}\)
= \(\frac{4}{6}\)
c) \(\frac{3}{8}-\frac{10}{2}:\frac{4}{5}\)
= \(\frac{3}{8}-\frac{25}{4}\)
= \(-\frac{47}{8}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có a+b+c-(a+b-2c)=-2-(-8)
<=>3c=6
=>c=2
=>a+b=-4; a-2b=-1
=>a+b-(a-2b)=-4-(-1)
<=>3b=-3
=>b=-1
=>a=-3
![](https://rs.olm.vn/images/avt/0.png?1311)
a) =3/11(-5/12+-7/12)-4/15
= 3/11.(-1)-4/15
=(-3)/11-4/15
=-89/165
a)
\(=\frac{3}{11}\left(\frac{-5}{12}+\frac{-7}{12}\right)-\frac{4}{15}\)
\(=\frac{3}{11}\left(\frac{-12}{12}\right)-\frac{4}{15}\)
\(=\frac{3}{11}\left(-1\right)-\frac{4}{15}\)
\(=\frac{3}{11}-\frac{4}{15}\)
\(=\frac{-89}{165}.\)