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`= -45 \div 18/7-0,5+1,25`
`= -17,5-0,5+1,25`
`= -18+1,25=-16,75`
Giải:
a) \(25\%-\dfrac{5}{4}+\dfrac{11}{6}\)
\(=\dfrac{1}{4}-\dfrac{5}{4}+\dfrac{11}{6}\)
\(=-1+\dfrac{11}{6}\)
\(=\dfrac{5}{6}\)
Vậy ...
b) \(75\%:\dfrac{11}{5}-\left(0,5\right)^2.\left(-7\right)+2,5\left(\dfrac{23}{3}-\dfrac{17}{3}\right)\)
\(=\dfrac{3}{4}:\dfrac{11}{5}-\dfrac{1}{4}.\left(-7\right)+2,5.2\)
\(=\dfrac{15}{44} +\dfrac{7}{4}+5\)
\(=\dfrac{23}{11}+5\)
\(=\dfrac{78}{11}\)
Vậy ...
c) \(45:\dfrac{18}{7}+50\%-1,25\)
\(=45:\dfrac{18}{7}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=\dfrac{35}{2}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=18-\dfrac{5}{4}\)
\(=\dfrac{67}{4}\)
Vậy ...
e: =>2/7-x=2/5
=>7-x=5
=>x=2
f: =>2x+3/3=10/3
=>2x+3=10
=>2x=7
=>x=7/2
g: =>(14+x)/7=15/7
=>x+14=15
=>x=1
h: =>(2x+3)/x=13/x
=>2x+3=13
=>2x=10
=>x=5
1/Ta co :
\(\dfrac{15}{7}.\left(\dfrac{1}{5}-\dfrac{46}{45}\right)+\dfrac{46}{45}.\left(\dfrac{15}{7}-\dfrac{45}{46}\right)\)
=\(\dfrac{15}{7}.\dfrac{1}{5}-\dfrac{15}{7}.\dfrac{46}{45}+\dfrac{46}{45}.\dfrac{15}{7}-\dfrac{46}{45}.\dfrac{45}{46}\)
=\(\dfrac{15}{7}.\left(\dfrac{1}{5}-\dfrac{46}{45}+\dfrac{46}{45}\right)-1\)
=\(\dfrac{15}{7}.\dfrac{1}{5}-1\)
=\(\dfrac{3}{7}-1=\dfrac{-4}{7}\)
2/Ta co
\(\dfrac{43}{47}.\left(\dfrac{18}{37}+\dfrac{47}{43}\right)-\dfrac{18}{3}.\left(\dfrac{43}{47}+\dfrac{37}{36}\right)\)
=\(\dfrac{43}{47}.\dfrac{18}{37}+\dfrac{43}{47}.\dfrac{47}{43}-\dfrac{18}{37}.\dfrac{43}{47}+\dfrac{18}{37}.\dfrac{37}{36}\)
=\(\dfrac{18}{37}.\left(\dfrac{43}{37}-\dfrac{43}{37}+\dfrac{37}{36}\right)+1\)
=\(\dfrac{18}{37}.\dfrac{37}{36}+1\)
=\(\dfrac{1}{2}+1=\dfrac{3}{2}\)
tick cho mk nha
a) 6,5% của 320m là 20,8 m
b) \(\dfrac{2}{7}\)của 21km là 6 km
c) 1,25 của 84 tấn là 105 tấn
d) \(1\dfrac{3}{4}\) của 1,25 giờ là 2,1875 giờ
e) \(1\dfrac{1}{4}\) của 2 giờ là 2,5 giờ
g) \(\dfrac{2}{11}\) của 22% là 4%
a: =3/4-5/4+3/2x12/5=-1/2+36/10=-5/10+36/10=31/10
b: \(=\dfrac{-7}{13}\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{7}{13}+8=8\)
\(45:\dfrac{7}{18}+50%-1,25\)
\(=45. \dfrac{18}{7}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=\dfrac{810}{7}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=\dfrac{1627}{14}-\dfrac{5}{4}\)
\(=\dfrac{3219}{28}\)
45: \(\dfrac{7}{18}\) + 50% - 1,25
= 45 x \(\dfrac{18}{7}\) + \(\dfrac{50}{100}\) - \(\dfrac{125}{100}\)
= \(\dfrac{810}{7}\)- \(\dfrac{75}{100}\)
= \(\dfrac{81000}{700}\) - \(\dfrac{525}{700}\)
=\(\dfrac{80475}{700}\)
=\(\dfrac{3219}{28}\)