Question

Найдите значение выражения при .+ при x= -1,5.

Answer 1

$\frac{5-3x}{25- x^{2} } + \frac{2x}{25- x^{2} } = \frac{5-3x+2x}{25- x^{2} } = \frac{5-x}{25- x^{2} } = \frac{5-x}{(5-x)(5+x)} = \frac{1}{5+x}$

При х=-1,5:
$\frac{1}{5+x}= \frac{1}{5+(-1,5)} = \frac{1}{5-1,5} = \frac{1}{3,5}=1: \frac{35}{10} =1* \frac{10}{35}= \frac{10}{35} = \frac{2}{7}$