Question

X x 3 + X x 7 = 700

Answer 1

\(\Leftrightarrow x\times\left(3+7\right)=700\\ \Leftrightarrow x\times10=700\\ \Leftrightarrow x=700:10\\ \Leftrightarrow x=70\)

Answer 2

\(x\times\)(3 + 7) = 700

\(x\times\)   10       = 700

\(x=700:10=70\)