tolong donk soal ini tentang limit

pakai rumus
(b - p)/2√a

b) lim  √9x² - √(9x² - 14x - 23)
   x->~
= (0 - (-14))/2√9
= 14/6
= 7/3

c) lim √(x² + 5x + 3) - √(x² + 6x + 9)
  x->~
= (5 - 6)/2√1
= - 1/2

d) lim  √(4x² - 4x + 3) - √(4x² - 7)
   x->~
= (- 4 - (- 7))/2√4
= 3/4