Разделите многочлен \(\displaystyle t^{\,2}+8t+15\) на многочлен \(\displaystyle t+3\) в столбик:

\(\displaystyle -\)	\(\displaystyle \phantom{\,\,} t^{\,2}+8t+15\)				\(\displaystyle t+3\)
	[ ]				[ ]
	\(\displaystyle \phantom{ x^{\,2}+} -\)	[ ]
		[ ]
		\(\displaystyle 0\phantom{ xx}\)

и запишите разложение:

\(\displaystyle t^{\,2}+8t+15=(t+3)\cdot \big(\)[ ]\(\displaystyle \big){\small . }\)