Câu 1:
a)$\frac{2}{9}$+$\frac{5}{9}$=$\frac{7}{9}$
b)$\frac{1}{5}$+$\frac{3}{7}$=$\frac{7+15}{35}$=$\frac{22}{35}$
c)$\frac{-22}{7}$.$\frac{21}{44}$-$\frac{-3}{2}$=$\frac{-3}{2}$-$\frac{-3}{2}$=0
d)$\frac{4}{13}$:$\frac{-2}{13}$= $\frac{4}{13}$. $\frac{-13}{2}$= $\frac{4.(-13)}{13.2}$=2
Câu 2:
x-5=17
=>x=17+5
=>x=22
Vậy x=22
Chúc học tốt!!
