Question

5 класс
Как это делать?

Answer 1

$\frac{21z^{2}}{t} : 3z = \frac{21z^{2}}{t} : \frac{3z}{1} = \frac{21z^{2}}{t} * \frac{1}{3z} = \frac{7z}{t} * \frac{1}{1} = \frac{7z}{t}$