[tex]\displaystyle\bf\\1)\\\\56x^{5}y^{14} \cdot\frac{2}{7} x^{2} y=\frac{56x^{5} y^{14} \cdot2x^{2} y}{7} =8\cdot 2\cdot x^{5+2}\cdot y^{14+1} =16x^{7} y^{15} \\\\\\2)\\\\-\frac{1}{3} p^{2}\cdot(-2+k)\cdot5pk=\Big(\frac{2}{3} p^{2} -\frac{1}{3} p^{2} k\Big) \cdot 5pk=\frac{10}{3} p^{3} k-\frac{5}{3} p^{3} k^{2} =\\\\\\=3\frac{1}{3} p^{3} k-1\frac{2}{3} p^{3} k^{2}[/tex]

[tex]\displaystyle\bf\\3)\\\\2\frac{1}{4}b^{2} c^{2} d^{3}\cdot\Big(-3\frac{1}{3} b^{3} c^{4} d^{7} \Big)=-\frac{9}{4} \cdot\frac{10}{3} \cdot b^{2+3} \cdot c^{2+4} \cdot d^{3+7} =\\\\\\=-7,5b^{5} c^{6} d^{10}[/tex]