Разделите многочлен \(\displaystyle 80z^{\,2}+42z+4\) на многочлен \(\displaystyle 10z+4\) в столбик:

\(\displaystyle -\)	\(\displaystyle \phantom{\,\,} 80z^{\,2}+42z+4\)				\(\displaystyle 10z+4\)
	[ ]				[ ]
	\(\displaystyle \phantom{ xxx\,\,} -\)	[ ]
		[ ]
		\(\displaystyle 0\phantom{ x}\)

и запишите разложение:

\(\displaystyle 80z^{\,2}+42z+4=(10z+4)\cdot \big(\)[ ]\(\displaystyle \big){\small . }\)