Đáp án:

a) $\frac{11}{2}$ - x = $\frac{7}{9}$ -$\frac{5}{18}$ 

$\frac{11}{2}$ - x =  $\frac{1}{2}$  

 x =  $\frac{11}{2}$ - $\frac{1}{2}$  

 x = 5

Vậy x = 5

b) $\frac{13}{15}$ - x = $\frac{11}{20}$ - $\frac{3}{10}$ 

$\frac{13}{15}$ - x = $\frac{1}{4}$ 

 x =   $\frac{13}{15}$ - $\frac{1}{4}$ 

 x = $\frac{37}{60}$ 

Vậy   x = $\frac{37}{60}$   

c) $\frac{17}{18}$ - x =$\frac{5}{6}$ - $\frac{7}{12}$ 

    $\frac{17}{18}$ - x = $\frac{1}{4}$ 

x =     $\frac{17}{18}$ - $\frac{1}{4}$ 

x = $\frac{25}{36}$ 

Vậy   x = $\frac{25}{36}$ 

d) $\frac{19}{16}$ - x = $\frac{13}{8}$ - $\frac{11}{12}$ 

    $\frac{19}{16}$ - x = $\frac{17}{24}$ 

x =  $\frac{19}{16}$ - $\frac{17}{24}$ 

x = $\frac{23}{48}$ 

Vậy  x = $\frac{23}{48}$

Chúc học tốt !!!