Question

Срочно!!!!
3 примера
30 балов

Answer 1

Пошаговое объяснение:

1)

(х/у² - 1/х) : (1/4 + 1/х) =

= (х² - у²)/(ху²) : (х + 4)/(4х) =

= (х - у²)/(ху²) * 4х/(х + 4) = 4(х-у²) / у²(х+4),

2)

(х+3)/(х²+9) * ((х+3)/(х-3) + (х-3)/(х+3)) =

= (х+3)/(х²+9) * ((х+3)(х+3) + (х - 3)(х - 3))/(х+3)(х-3) =

= (х+3)/(х²+9) * ((х²+6х+9) + (х²-6х+9))/(х+3)(х-3) =

= (х+3)/(х²+9) * (2х²+18)/(х+3)(х-3) =

= (х+3)/(х²+9) * 2(х²+9)/(х+3)(х-3) =  2/(х-3),

3)

2х² - 5х - 3 = 0,

Д = (-5)² - 4*2*(-3) = 25 + 24 = 49,

х1 = (5 + 7) / 2*2 = 12/4 = 3,

х2 = (5 - 7) / 2*2 = -2/4 = -0,5,

2х² - 5х - 3 = 2 * (х - 3)(х + 0,5) = (х - 3)(2х + 1)