Question

 

Answer 1

\(a,\dfrac{-13}{24}+x=\dfrac{9}{20}\\ x=\dfrac{9}{20}+\dfrac{13}{24}\\ x=\dfrac{119}{120}\)

\(b,\dfrac{10}{19}-\dfrac{5}{21}+\dfrac{9}{19}-\dfrac{16}{21}\\ =\left(\dfrac{10}{19}+\dfrac{9}{19}\right)-1\left(\dfrac{5}{21}+\dfrac{16}{21}\right)\\ =1-1\\ =0\)

 

Answer 2

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Answer 3

a: x=9/20+13/24=54/120+65/120=119/120

b; =10/19+9/19-5/21-16/21=1-1=0