18=3|4x-10|

18=3|4x-10|         x = ?

$\begin{array}{|rcll|} \hline 3|4x-10| &=& 18 \quad & | \quad :3 \\ |4x-10| &=& 6 \quad &|\quad \text{square both sides} \\ (4x-10)^2 &=& 6^2 \\ (4x-10)^2 &=& 36 \\ 16x^2-80x+100 &=& 36 \quad & | \quad -36 \\ 16x^2-80x+64 &=& 0 \quad & | \quad :16 \\ x^2-5x+ 4 &=& 0\\ (x-4)(x-1) &=& 0\\ x-4 = 0 & \text{or} & x-1 = 0 \\ x = 4 & \text{or} & x = 1 \\ \hline \end{array}$