x={1,2,3,……..20}R1={(x,y):2x−3y=2}R2={(x,y):−5x+4y=0} $\begin{aligned}
& \mathrm{R}_1={(4,2),(7,4),(10,6),(13,8),(16,10),(19,12)} \
& \mathrm{R}_2={(4,5),(8,10),(12,15),(16,20)}
\end{aligned}inR_1 6elementneededinR_2 4elementneededSo,total6+4=10$ element