Open the bracket on LHS by multiplying with -1/3 and RHS by multiplying with -5 with quantity inside the bracket.
[tex]\begin{gathered} \frac{-1}{3}\times6x-(\frac{-1}{3}\times21)=-5\times x+(-5)\times1 \\ -2x-(-7)=-5x-5 \\ -2x+7=-5x-5 \end{gathered}[/tex]Add '5x' to LHS (Left-hand side) and RHS (Right-hand side) of the above expression to eliminate the 5x in the RHS.
[tex]\begin{gathered} -2x+7+(5x)=-5x-5+(5x) \\ (-2x+5x)+7=(-5x+5x)-5 \\ 3x+7=0x-5 \\ 3x+7=-5 \end{gathered}[/tex]Substract '7' from both RHS and LHS of the above expression.
[tex]\begin{gathered} 3x+7-(7)=-5-(7) \\ 3x+0=-12 \\ 3x=-12 \end{gathered}[/tex]Divide '3' from the RHS and LHS of the above expression.
[tex]\begin{gathered} \frac{3x}{3}=\frac{-12}{3} \\ x=-4 \end{gathered}[/tex]Thus, the value of x is -4.
