Question

[( 7x -63 ) : 3 - 105 ] . 6 = 840

Answer 1

\(\left[\left(7x-63\right):3-105\right]\cdot6=840\)

\(\Rightarrow\left(7x-63\right):3-105=840:6\)

\(\Rightarrow\left(7x-63\right):3-105=140\)

\(\Rightarrow\left(7x-63\right):3=140+105\)

\(\Rightarrow\left(7x-63\right):3=245\)

\(\Rightarrow7x-63=245\cdot3\)

\(\Rightarrow7x-63=735\)

\(\Rightarrow7x=735+63\)

\(\Rightarrow7x=798\)

\(\Rightarrow x=\dfrac{798}{7}=114\)