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\(\frac{145,7-290:5+0,3}{x:8+13}=4\)

=> \(\frac{145,7-58+0,3}{x:8+13}=4\)

=> \(\frac{88}{x:8+13}=4\)

=> \(x:8+13=88:4\)

=> \(x:8+13=22\)

=> x : 8 = 9

=> x = 9 x 8 = 72

Vậy x = 72

\(x = {-b \pm \s\)

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)

= \(\frac{145,7-58+0,3}{X:8+13}=4\)

=\(\frac{87,7+0,3}{X:8+13}=4\)

= \(\frac{90}{X:8+13}=4\)

X : 8 + 13 = 90 : 4

X : 8 + 13 = 22,5

X : 8 = 22,5 - 13

X : 8 = 9,5

X = 9,5 x 8 

X = 76

\(\frac{145,7-290\div5+0,3}{x\div8+13}=4\)

\(\frac{88}{x\div8+13}=4\)

\(x\div8+13=88\div4\)

\(x\div8+13=22\)

\(x\div8=22-13\)

\(x\div8=9\)

\(x=9\times8\)

\(x=72\)

76 moi dung tao cung ra the

a) \(\frac{58}{19}+\frac{13}{17}+\frac{35}{43}+\frac{119}{19}+\frac{8}{43}\)

\(=\frac{13}{17}+\left(\frac{58}{19}+\frac{119}{19}\right)+\left(\frac{35}{43}+\frac{8}{43}\right)\)

\(=\frac{13}{17}+\frac{204}{19}+1\)

\(=\frac{1808}{133}\)

b) \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}+\frac{13}{4}\)

\(=\frac{-5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{13}{4}\)

\(=\frac{-5}{7}.1+\frac{13}{4}\)

\(=\frac{71}{28}\)

c) \(\frac{146}{13}-\left(\frac{21}{7}+\frac{68}{13}\right)\)

\(=\left(\frac{164}{13}-\frac{68}{13}\right)+3\)

\(=\frac{135}{13}\)

d) \(\frac{2}{7}.\frac{21}{4}-\frac{2}{7}.\frac{13}{4}\)

\(=\frac{2}{7}.\left(\frac{21}{4}-\frac{13}{4}\right)\)

\(=\frac{2}{7}.\frac{8}{4}\)

\(=\frac{4}{7}\)

P/s: Mk ko chắc nữa!

b: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{13}{4}=\dfrac{-5}{7}+\dfrac{13}{4}=\dfrac{-20+91}{28}=\dfrac{71}{28}\)

c: \(=\dfrac{146}{13}-3-\dfrac{68}{13}=6-3=3\)

d: \(=\dfrac{2}{7}\left(\dfrac{21}{4}-\dfrac{13}{4}\right)=\dfrac{4}{7}\)