Tolong dijawab, besok dikumpulkan, no 9 sampai 13, pakai caranya

Limit

9. lim (x->1) { 2x² - ax + 1} /(x² - 4x +5 ) = 1/6
x  = 1 --> bentuk 0/0

x = 1 --> 2x² - ax + 1 =0
2(1)² - a(1) +1 = 0
2 - a + 1 = 0
3 - a = 0
a = 3

10.
lim (x->∞) {(2x+1)(x+3)} /(3x² + 5x +2)
lim(x->∞)  ( 2x²  + 7x + 3)/ (3x² + 5x + 2)
= 2/3

11.
lim(x->∞)  √(x² + 2x -5) - √(x²-3x +2)
a = 1, b = 2 , c  = 5  , p = 1 , q = -3, r = 2
a= p
limit (x->∞)  = (b - q)/ (2√a)
= (2 - (-3)) /  2√(1)
= (2+3)/ (2)
= 5/2

12.
lim f² (x) + g²(x) =  { f(x)}² + {g(x)}² = (2)² + (-1)² = 4+1 = 5

13.
lim 3. f(a) - 5 g(a) = 3(12) - 5(3) = 36 - 15 = 21