Selesaikanlah Persoalan Matematika Berikut no12-14 dengan Menggunakan Cara

12.

Lim √x - √2x - 1 / x - 1
x→1

Lim √x - √2x - 1 (√x + √2x - 1)
x→1 . . . . / x - 1 (√x + √2x - 1)

Lim x - (2x - 1) / x - 1 (√x + √2x - 1)
x→1

Lim -x + 1 / x - 1 (√x + √2x - 1)
x→1

Lim - (x - 1) / (x - 1)(√x + √2x - 1)
x→1

Lim -1 / √x + √2x - 1
x→1 

= -1 / √1 + √2(1) - 1

= -1 / 1 + √2 - 1

= -1 / 1 + 1

= -1/2

13.

Lim x - 1 / √x² + 3 - 2
x→1

Lim x - 1 (√x² + 3 + 2)
x→1 .. / (√x² + 3 + 2)(√x² + 3 - 2)

Lim (x - 1)(√x² + 3 + 2)
x→1 .. / x² + 3 - 4

Lim (x - 1)(√x² + 3 + 2) / (x² - 1)
x→1

Lim (x - 1)(√x² + 3 + 2) / (x - 1)(x + 1)
x→1

Lim (√x² + 3 + 2) / x + 1
x→1

= √1² + 3 + 2 / 1 + 1

= √4 + 2 / 2

= 2 + 2 / 2

= 4/2

= 2

14.

Lim [ 2x + 1 / 2 - √4x + 6 ]
x→-1/2

Lim [ (2x + 1)(2 + √4x + 6)
x→-1/2 .. / (2 - √4x + 6)(2 + √4x + 6) ]

Lim (2x + 1)(2 + √4x + 6)
x→-1/2 .. / (4 - (4x + 6)

Lim (2x + 1)(2 + √4x + 6)
x→-1/2 .. / (4 - 4x - 6)

Lim (2x + 1)(2 + √4x + 6)
x→-1/2 .. / (-4x - 2)

Lim (2x + 1)(2 + √4x + 6)
x→-1/2 .. / -2 (2x + 1)

Lim (2 + √4x + 6)
x→-1/2 .. / -2

= 2 + √4(-1/2) + 6 / -2

= 2 + √-2 + 6 / - 2

= 2 + √4 / -2

= 2 + 2 / -2

= 4/ - 2

= -2