tính bằng cách thuận tiện nhất : 5/9*5/11+5/11*4/9
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
`5/9+5/11+4/9+4/11+2/11`
`=(5/9+4/9)+(5/11+4/11+2/11)`
`=9/9+11/11`
`=1+1`
`=2`
(2/7+5/7)+4/9=1+4/9=13/9
17/11+(7/15+5/11)=17/11+7/15+5/11=(17/11+5/11)+7/15=2+5/11=27/11
A = ( 2/7 + 5/7 ) + 4/9
A = 1 + 4/9
A = 13/9
B = ( 17/11 + 5/11 ) + 7/15
B = 2 + 7/15
B = 37/15
Chúc bạn học tốt~^^
A = 2/7 + 4/9 + 5/7
A = ( 2/7 + 5/7 ) + 4/9
A = 1 + 4/9
A = 13/9
Phần B làm tương tự bằng cách bỏ ngoặc nhé !
\(=\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)+\left(\dfrac{11}{16}+\dfrac{5}{16}\right)=1+1+1=3\)
\(=\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)+\left(\dfrac{11}{16}+\dfrac{5}{16}\right)\\ =1+1+1=3\)
=(1/11+10/11)+(2/11+9/11)+(3/11+8/11)+(4/11+7/11)+(5/11+6/11)
=11/11+11/11+11/11+11/11+11/11
=1+1+1+1+1
=5
a: \(=\dfrac{21}{11}+\dfrac{12}{11}+\left(-\dfrac{9}{19}-\dfrac{3}{19}-\dfrac{6}{19}\right)=3-\dfrac{18}{19}=\dfrac{39}{19}\)
b: \(=\dfrac{2}{3}+\dfrac{4}{3}+\dfrac{3}{4}+\dfrac{7}{4}+\dfrac{4}{5}+\dfrac{16}{5}=2+4+\dfrac{5}{2}=6+\dfrac{5}{2}=\dfrac{17}{2}\)
\(\dfrac{5}{9}\times\dfrac{5}{11}+\dfrac{5}{11}\times\dfrac{4}{9}\)
\(=\left(\dfrac{5}{9}+\dfrac{4}{9}\right)\times\dfrac{5}{11}\)
\(=1\times\dfrac{5}{11}\)
\(=\dfrac{5}{11}\)
#NoSimp
\(\dfrac{5}{9}\) \(\times\) \(\dfrac{5}{11}\) + \(\dfrac{5}{11}\) \(\times\) \(\dfrac{4}{9}\)
= \(\dfrac{5}{11}\) \(\times\) ( \(\dfrac{5}{9}\) + \(\dfrac{4}{9}\))
= \(\dfrac{5}{11}\) \(\times\) \(\dfrac{9}{9}\)
= \(\dfrac{5}{11}\)