\(3\times\dfrac{7}{10}+\dfrac{7}{10}\times5+2\times\dfrac{7}{10}\)
\(=\dfrac{7}{10}\times\left(3+5+2\right)\)
\(=\dfrac{7}{10}\times10\)
\(=\dfrac{70}{10}=7\)
3 x\(\dfrac{7}{10}\)+\(\dfrac{7}{10}\)x5+2 x\(\dfrac{7}{10}\)
=\(\dfrac{7}{10}\) x(3+5+2)
= \(\dfrac{7}{10}\) x 10
=7