\[\boxed{\mathbf{Стр.\ 37.\ }еуроки - ответы\ на\ пятёрку}\]
\[\boxed{\mathbf{46.}}\]
\[\boxed{\mathbf{47.}}\]
\[2500 \cdot (2 \cdot 3) = 5000 \cdot 3 =\]
\[= 15\ 000\]
\[3100 \cdot (3 \cdot 10) = 9300 \cdot 10 =\]
\[= 93\ 000\]
\[\boxed{\mathbf{48.}}\]
\[x \cdot 8 = 180 + 140\]
\[x \cdot 8 = 320\]
\[x = 320\ :8\]
\[x = 40.\]
\[x\ :5 = 300 - 150\]
\[x\ :5 = 150\]
\[x = 150 \cdot 5\]
\[x = 750.\]