`x+3/5=7/6`

`=>x=7/6-3/5`

`=>x=35/30-18/30`

`=>x=17/30`

x+3/5=7/6

x       =7/6-3/5

x       =35/30-18/30

x       =17/30

\(\dfrac{63}{45}-\dfrac{20}{25}=\dfrac{7}{5}-\dfrac{4}{5}=\dfrac{3}{5}\)

\(\dfrac{36}{21}-\dfrac{15}{20}=\dfrac{720}{420}-\dfrac{315}{420}=\dfrac{405}{420}=\dfrac{27}{28}\)

\(\dfrac{36}{21}-\dfrac{15}{20}=\dfrac{12}{7}-\dfrac{3}{4}=\dfrac{27}{28}\)

`2+3/4`

`=8/4+3/4`

`=11/4`

11/4

\(\dfrac{2}{5}+\dfrac{1}{4}=\dfrac{8}{20}+\dfrac{5}{20}=\dfrac{13}{20}\)
\(\dfrac{1}{3}+\dfrac{3}{5}=\dfrac{5}{15}+\dfrac{9}{15}=\dfrac{14}{15}\)
\(\dfrac{1}{2}+\dfrac{1}{4}=\dfrac{2}{4}+\dfrac{1}{4}=\dfrac{3}{4}\)
\(\dfrac{1}{8}+\dfrac{5}{6}=\dfrac{3}{24}+\dfrac{20}{24}=\dfrac{23}{24}\)

ĐÂSDWADAS

= 5/7 - 1/7 

= 4/6

mk lm lại ạ!

= 5/7 - 1/7

= 4/7

\(\dfrac{5}{11}-\left(\dfrac{3}{5}-\dfrac{6}{11}\right)\)
\(=\dfrac{5}{11}-\dfrac{3}{5}+\dfrac{6}{11}\)
\(=\left(\dfrac{5}{11}+\dfrac{6}{11}\right)-\dfrac{3}{5}\)
\(=1-\dfrac{3}{5}\)
\(=\dfrac{5}{5}-\dfrac{3}{5}\)
\(=\dfrac{2}{5}\)

`5/11-(3/5-6/11)`

`=5/11-3/5+6/11`

`=(5/11+6/11)-3/5`

`=1-3/5`

`=2/5`

Tổng của 2 số là:
\(45\times2=90\)
Gọi a là số lớn và b là số bé.
Theo đề bài,ta có:
\(a-b=3\times b\)
\(a=3\times b+b\)
\(a=3\times b+1\times b\)
\(a=\left(3+1\right)\times b\)
\(a=4\times b\)
Do đó số lớn gấp 4 lần số bé.
Số lớn là:
\(90:\left(4+1\right)\times4=72\)

số lớn là :

(45 + 3) : 2 = 24 

5 x 5 = 25 

123456789 x 123456789 = 15241578750190521