Bantuin soal limit ya

Lim (ax + b - √x) / (x - 4)
x=>4
Akan menghasilkan 3/4 jika setelah diturunkan (L'HOSPITAL)
Lim (ax + b - x^1/2) / (x - 4)
x=>4

Lim (a - 1/2 x^(-1/2)) / 1 = 3/4
x=>4

a - 1/2 . 1/√4 = 3/4
a - 1/4 = 3/4
a = 4/4 = 1

Jika kita substitusi x = 4 langsung maka akan menghasilkan 0/0
Lim (ax + b - √x) / (x - 4)
x=>4

(4a + b - √4) / (4 - 4) = 0/0
4(1) + b - 2 = 0
2 + b = 0
b = -2

a + b = 1 + (-2) = -1