Question

срочно нужно 4,5 и 6 задание.

Answer 1

$4)\frac{a^{-6}}{a^{-7}*a^{2}}=a^{-6-(-7)-2}=a^{-6+7-2}=a^{-1}\\\\a^{-1}=(\frac{1}{5})^{-1}=5\\\\5)\frac{\sqrt{6} }{\sqrt{3}*\sqrt{8}}=\frac{\sqrt{3*2}}{\sqrt{3}*\sqrt{4*2}}=\frac{\sqrt{3} *\sqrt{2} }{\sqrt{3}*2\sqrt{2}}=\frac{1}{2}=0,5$

$6)\frac{5c-c^{2} }{c^{2}-25}=\frac{c(5-c)}{(c-5)(c+5)}=-\frac{c}{c+5}$