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a) \(\frac{2}{3}+\frac{5}{4}=\frac{8}{12}+\frac{15}{12}\)
\(=\frac{8+15}{12}=\frac{23}{12}\)
b) \(\frac{15}{25}+\frac{6}{21}=\frac{3}{5}+\frac{2}{7}\)
\(=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
c) \(\frac{35}{11}-2=\frac{35}{11}-\frac{22}{11}\)
\(=\frac{13}{11}\)
d) \(\frac{68}{17}-3=\frac{68}{17}-\frac{51}{17}\)
\(=1\)
a) \(x+\frac{4}{5}=\frac{3}{2}\)
\(\Rightarrow x=\frac{3}{2}-\frac{4}{5}\)
\(\Rightarrow x=\frac{7}{10}\)
Vậy \(x=\frac{7}{10}.\)
b) \(x-\frac{3}{2}=\frac{11}{4}\)
\(\Rightarrow x=\frac{11}{4}+\frac{3}{2}\)
\(\Rightarrow x=\frac{17}{4}\)
Vậy \(x=\frac{17}{4}.\)
c) \(\frac{25}{3-x}=\frac{5}{6}\)
\(\Rightarrow\left(3-x\right)5=25.6\)
\(\Rightarrow15-5x=150\)
\(\Rightarrow5x=15-150\)
\(\Rightarrow5x=-135\)
\(\Rightarrow x=-135:5\)
\(\Rightarrow x=-27\)
Vậy \(x=-27.\)
1a) \(\frac{12}{17}+\frac{19}{17}+\frac{8}{17}\)
\(=\left(\frac{12}{17}+\frac{8}{17}\right)+\frac{19}{17}\)
\(=\frac{20}{17}+\frac{19}{17}\)
\(=\frac{39}{17}\)
b) \(\frac{2}{5}+\frac{7}{12}+\frac{13}{12}\)
\(=\frac{2}{5}+\frac{5}{3}\)
\(=\frac{31}{15}\)
2) \(\frac{25}{3}-x=\frac{5}{6}\)
\(x=\frac{25}{3}-\frac{5}{6}\)
\(x=\frac{45}{6}\)
ủng hộ tớ nha
a) 4 - 2/7 = 28/7 - 2/7
= 26/7
b) 5 - 17/19 = 95/19 - 17/19
= 78/19
c) 35/11 - 2 = 35/11 - 22/11
= 13/11
d) 68/17 - 3 = 4 - 3
= 1
nha bn
a) \(\left(\frac{1}{3}+\frac{1}{5}\right)\times x=\frac{8}{25}\)
\(\frac{8}{15}\times x=\frac{8}{25}\)
\(x=\frac{8}{25}:\frac{8}{15}\)
\(x=\frac{3}{5}\)
Vậy x = 3/5
b) \(\frac{1}{2}:\frac{4}{5}:x=\frac{7}{3}\)
\(\frac{5}{8}:x=\frac{7}{3}\)
\(x=\frac{5}{8}:\frac{7}{3}\)
\(x=\frac{15}{56}\)
Vậy x = 15/36
ủng hộ tớ nha. thank you nhìu
a) (1/3 + 1/5) . x = 8/25
(5/15 + 3/15) . x = 8/25
=> 8/15 . x = 8/25
x = 8/25 : 8/15
x = 3/5
Vậy x = 3/5
Bài 2 :
a) Tìm x
\(x:\frac{2}{3}=\frac{1}{2}\)
\(x=\frac{1}{2}\times\frac{2}{3}\)
\(x=\frac{1}{3}\)
Vậy \(x=\frac{1}{3}\)
b) Tính giá trị của biểu thức :
\(\frac{5}{7}\times\frac{3}{5}-\frac{10}{14}\times\frac{2}{15}\)
\(=\frac{5}{7}\times\frac{3}{5}-\frac{5}{7}\times\frac{2}{15}\)
\(=\frac{5}{7}\times\left(\frac{3}{5}-\frac{2}{15}\right)\)
\(=\frac{5}{7}\times\frac{7}{15}\)
\(=\frac{1}{3}\)
ủng hộ tớ nha.
Bài 2:
a) x : 2/3 = 1/2
x = 1/2 x 2/3
x = 1/3
b) 5/7 x 3/5 - 10/14 x 2/15
= 3/7 - 5/7 x 2/15
= 3/7 - 2/21 (tự quy đồng)
= 1/3
Bài 1
a 2/5+3/6=12/30+15/30=27/30=9/10 .
b 5/9-1/6=30/54-9/54=21/54=7/18
a] 4/12 ; 5/12 ; 11/2 ; 1/4
b] 1 ; 9/12; 12/5 ; 11/3
c] 8/21; 6/11;8/7
d] 2/3 ;2/7 15/2
a]1/3 5/12 11/2 1/4
b]1 3/4 12/5 33/9
c]8/21 6/11 8/7
d]2/3 2/7 15/2
\(a,\frac{4}{5}+\frac{17}{25}\)
\(=\frac{20}{25}+\frac{17}{25}\)
\(=\frac{37}{25}\)
\(b,\frac{7}{3}-\frac{5}{6}\)
\(=\frac{14}{6}-\frac{5}{6}\)
\(=\frac{9}{6}\)
\(=\frac{3}{2}\)
\(c,1+\frac{2}{3}\)
\(=\frac{3}{3}+\frac{2}{3}\)
\(=\frac{5}{3}\)
a) 4/5 + 17/25
= 20/25 + 17/25
= 37/25
b) 7/3 - 5/6
= 14/6 - 5/6
= 9/6
= 3/2
c) 1 + 2/3
= 3/3 + 2/3
= 5/3