\[\boxed{\text{54\ (54).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[2x + 5 < 3x\]
\[1)\ x = 4,2:\]
\[2x + 5 = 2 \cdot 4,2 + 5 = 8,4 + 5 =\]
\[= 13,4;\]
\[3x = 3 \cdot 4,2 = 12,6.\]
\[Неравенство\ 2x + 5 < 3x -\]
\[неверно.\]
\[2)\ x = 5:\]
\[2x + 5 = 2 \cdot 5 + 5 = 10 + 5 =\]
\[= 15;\]
\[3x = 3 \cdot 5 = 15.\]
\[Неравенство\ 2x + 5 < 3x -\]
\[неверно.\]
\[3)\ x = 6,5:\]
\[2x + 5 = 2 \cdot 6,5 + 5 = 13 + 5 =\]
\[= 18;\]
\[3x = 3 \cdot 6,5 = 19,5.\]
\[Неравенство\ 2x + 5 < 3x -\]
\[верно.\]