`text{#Paow}`
`a,x+7`$\dfrac{4}{5}$`=9`$\dfrac{7}{15}$
`x+`$\dfrac{39}{5}$=$\dfrac{142}{15}$
`->x=`$\dfrac{142}{15}$-$\dfrac{39}{5}$
`x=`$\dfrac{142}{15}$-$\dfrac{117}{15}$
`x=`$\dfrac{5}{3}$
`=>` Vậy `x` có giá trị là$\dfrac{5}{3}$
`b,x-4`$\dfrac{9}{11}$=$\dfrac{2121}{2222}$
`x-`$\dfrac{53}{11}$=$\dfrac{21}{22}$
`->x=`$\dfrac{21}{22}$+$\dfrac{53}{11}$
`x=`$\dfrac{21}{22}$+$\dfrac{106}{22}$
`x=`$\dfrac{127}{22}$
`=>`Vậy `x` có giá trị là $\dfrac{127}{22}$
