mk giải đầu tiên nhé **** mk đi

a)43/60

b)-83/84

(5/11 + 6/11) + (13/21 + 8/21)
= 1 + 1
= 2

\(\dfrac{5}{11}+\dfrac{13}{21}+\dfrac{6}{11}+\dfrac{8}{21}\\ =\left(\dfrac{5}{11}+\dfrac{6}{11}\right)+\left(\dfrac{13}{21}+\dfrac{8}{21}\right)\\ =\dfrac{11}{11}+\dfrac{21}{21}\\ =1+1\\ =2\)

= (5/11 + 6/11) + (13/21 + 8/21)

=     1 + 1

= 2

Vậy giá trị biểu thức là 2

Bài 1: 

a: x/-2=-18/x

=>x²=36

=>x=6 hoặc x=-6

b: x/2+x/5=17/10

=>7/10x=17/10

hay x=17/7

ai mần tr mình cho tick

\(\frac{5}{11}+3\frac{8}{21}+\frac{6}{11}-\frac{8}{21}\)

\(=\frac{5}{11}+\frac{71}{21}+\frac{6}{11}-\frac{8}{21}\)

\(=\left(\frac{5}{11}+\frac{6}{11}\right)+\left(\frac{71}{21}-\frac{8}{21}\right)\)

\(=1+3\)

\(=4\)

Đúng lun, Mn tk mk nha!

\(\frac{5}{11}+3\frac{8}{21}+\frac{6}{11}-\frac{8}{21}\)

=\(\frac{5}{11}+\frac{71}{21}+\frac{6}{11}-\frac{8}{21}\)

=\(\left(\frac{5}{11}+\frac{6}{11}\right)+\left(\frac{71}{21}-\frac{8}{21}\right)\)

=\(1+3\)

=

mik quên chưa ghi đáp án, xin lỗi nha

\(\frac{5}{11}+3\frac{8}{21}+\frac{6}{11}-\frac{8}{21}\)

=\(\frac{5}{11}+\frac{71}{21}+\frac{6}{11}-\frac{8}{21}\)

=\(\left(\frac{5}{11}+\frac{6}{11}\right)+\left(\frac{71}{21}-\frac{8}{21}\right)\)

=\(1+3\)

=\(4\)

= \(\frac{-7}{21}+\frac{8}{24}=0\)

\(\dfrac{5}{13}+\dfrac{-5}{17}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}\)

\(=\left(\dfrac{5}{13}+\dfrac{8}{13}\right)+\dfrac{-5}{17}+\left(\dfrac{-20}{41}-\dfrac{21}{41}\right)\)

\(=\dfrac{13}{13}+\dfrac{-5}{17}+\dfrac{-41}{41}\)

\(=1-\dfrac{5}{17}-1\)

\(=-\dfrac{5}{17}\)