`( 2.x - 15 )^5 = ( 2.x - 15 )^3`
`( 2.x - 15 )^5 - ( 2.x - 15 )^3=0`
`( 2.x - 15 )^3[ ( 2.x - 15 )^2-1]=0`
`<=>`\(\left[ \begin{array}{l}( 2.x - 15 )^3=0 \\ ( 2.x - 15 )^2-1=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x-15=0\\(2x-15)^2=1\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=\dfrac{15}{2}\\\left[ \begin{array}{l}2x-15=1\\2x-15=-1\end{array} \right.⇔\left[ \begin{array}{l}x=8\\x=7\end{array} \right.\end{array} \right.\)
`=>x={15/2;7;8}`
