Question

найдите значения выражения . a^2+6a+9 дробь a^2-9:10a+30 дробь a^2+3a при a= 15

Answer 1

$\frac{a^2+6a+9}{a^2-9} : \frac{10a+30}{a^2+3a} = \frac{(a+3)^2}{(a-3)(a+3)} * \frac{a(a+3)}{10(a+3)} = \frac{a+3}{a-3} * \frac{a}{10} = \frac{a(a+3)}{10(a-3)} \\ \frac{15(15+3)}{10(15-3)} = \frac{15*18}{10*12= \frac{9}{4} }$