Jawaban:

12.B

13. C

14. B

15. D

16. B

17. -

18. C

19. A

20. D

Penjelasan dengan langkah-langkah:

12.

√3 + √12 - √48

√3 + √4.3 - √16.3

1√3 + 2√3 - 4√3

3√3 - 4√3

-1√3

-√3

13.

0,00493 =

493 . 10^-5

atau

49,3 . 10^-4

14.

(2x +1) | (x-3)

2x + 1 = 0 | x - 3 = 0

2x = -1 | x = 3

x = -1/2

jadi Hp {-1/2,3}

15.

2x²-5x=7

2x² - 5x - 7 = 0

2x² - 5x - 14

_____________ = 0

2

(2x + 2) (2x - 7)

___________ = 0

2

(x+1) (2x-7) = 0

x = -1 | 2x = 7

| x = 7/2

| x = 3 1/2

Hp {3 1/2, -1}

16.

6x² - 16x + 8 = 0

cari faktor dari 8

diperoleh 4 dan 2

(2x - 4) (3x - 2)

17.

-

18.

x² - 10x = 25

x² - 10x - 25 = 0

a = 1 | b = -10 | c = -25

x1 + x2 = -b/a

-b/a

-(-10)/1

10/1

10

19.

2x² +6x + 8 = 0

2x² +6x +16

_________ = 0

2

(2x + 8) (2x + 2)

__________ = 0

2

2x + 8 = 0 | x + 1 = 0

2x = -8 | x = -1

x = -8/2

jadi persamaan memiliki dua akar berbeda

20.

3x² - x - 2 = 0

3x² - x - 6 : 3

(3x + 2) (3x - 3) : 3

3x = -2 | x -1 = 0

x = -2/3 | x = 1

(p) | (q)

p+1

-2/3 + 1

-2/3 + 3/3

1/3

q+1

1+1

2

(x - p+1)(x - q+1) = 0

(x - 1/3)(x-2) = 0

x² -2x -1/3x +2/3 = 0 kali dengan 3

3x² - 6x - 1x + 2 = 0

3x² -7x + 2 = 0