Question

найдите значения выражение ​

Answer 1

39.6

1) $\frac{x^{2}+1}{x-3} - \frac{10}{x-3} = \frac{x^{2}+1-10}{x-3} = \frac{x^{2}-9}{x-3} = \frac{(x-3)(x+3)}{x-3} = x+3$

При x = 57:

57 + 3 = 60

Ответ: 60

2) $\frac{y+7}{y^{2}-25} - \frac{2y+2}{y^{2}-25} = \frac{y+7}{(y-5)(y+5)} - \frac{2y+2}{(y-5)(y+5)} = \frac{y+7-(2y+2)}{(y-5)(y+5)} = \frac{y+7-2y-2}{(y-5)(y+5)} = \frac{-y+5}{(y-5)(y+5)} = \frac{-(y-5)}{(y+5)(y-5)} = -\frac{1}{y+5}$

При y = 5,7:

$-\frac{1}{5,7+5} = -\frac{1}{10,7} = -\frac{10}{107}$

Ответ: $-\frac{10}{107}$

3) $\frac{a^{2} - 16}{a-3} + \frac{7}{a-3} = \frac{a^{2}-16+7}{a-3} = \frac{a^{2}-9}{a-3} = \frac{(a-3)(a+3)}{a-3} = a+3$

При a = 33,25:

33,25 + 3 = 36,25

Ответ: 36,25

4) $\frac{9b-1}{b^{2}-9} - \frac{6b-10}{b^{2}-9} = \frac{9b-1-(6b-10)}{(b-3)(b+3)} = \frac{9b-1-6b+10}{(b-3)(b+3)} = \frac{3b+9}{(b-3)(b+3)} = \frac{3(b+3)}{(b-3)(b+3)} = \frac{3}{b-3}$

При b = 4,5:

$\frac{3}{4,5-3} = \frac{3}{1,5} = 2$

Ответ: 2