Question

7 класс !!!! Помогите /?

Answer 1

$frac{3a^2+12}{10a}:frac{a^4-16}{3a-6}= frac{3(a^2+4)}{10a} cdot frac{3(a-2)}{(a^2+4)(a-2)(a+2)} = frac{9}{10a(a+2)} = frac{9}{10cdot (-9)cdot (-9+2)} =\\= frac{9}{630}= frac{1}{70}$

$frac{c^9-1}{5c^2+5c+5} : frac{4c^6+4c^3+4}{10c+10} =frac{(c^3-1)(c^6+c^3+1)}{5(c^2+c+1)}cdot frac{10(c+1)}{4(c^6+c^3+1)} =\\= frac{(c-1)(c^2+c+1)}{5(c^2+c+1)} cdot frac{5(c+1)}{2} = frac{(c-1)(c+1)}{2}= frac{(-3-1)(-3+1)}{2} = frac{8}{2} =4$