1.
2.
\(\begin{array}{rcll} 9 \cdot (x-3) &=& 10\cdot 18 \\ 9x - 27 &=& 180 \\ 9x &=& 180 + 27 \\ 9x &=& 207 \\ x &=& 23 \end{array}\)
\(\begin{array}{lcll} x^2 &=& 9\cdot (9+7) \\ x^2 &=& 9\cdot 16 \\ x^2 &=& 144 \\ x &=& 12 \\ \end{array}\)
