Tolong besok mau dikumpulkan 16 sampai 20

16.
3x² + 7x – 6 = 0
3x² + 9x – 2x – 6 = 0
3x(x + 3) – 2(x + 3) = 0
(3x – 2)(x + 3) = 0

3x – 2 = 0
3x = 2
x = 2/3

dan

x + 3 = 0
x = -3

HP = {-3, 2/3}
Jawaban C

17.
5x² – 2x – 3 = 0
5x² – 5x + 3x – 3 = 0
5x(x – 1) + 3(x – 1) = 0
(5x + 3)(x – 1) = 0

5x + 3 = 0
5x = -3
x = -3/5

dan
x – 1 = 0
x = 1

Jawaban B

18.
misal
bilangan bulat tsb adalah a dan b
maka
a + b = 3
a = 3 – b

a . b = -108
(3 – b) . b = -108
3b – b² = -108
b² – 3b – 108 = 0
(b + 9)(b – 12) = 0

b + 9 = 0
b = -9

dan

b – 12 = 0
b = 12

Jawaban C

19.
L = 396 m²
l = p – 4

L = p x l
L = p x (p – 4)
396 = p² – 4p
p² – 4p – 396 = 0
(p + 18)(p – 22) = 0

p + 18 = 0
p = -18 (tidak memenuhi, karena ukuran panjang tidak mungkin negaitf)

p – 22 = 0
p = 22

l = p – 4
l = 22 – 4
l = 18

maka
panjang = 22 m
lebar = 18 m

Keliling = 2(p + l)
K = 2(22 + 18)
K = 2 x 40
K = 80 m

Jawaban C

20.
Luas = 180 m²
P x L = 180

Keliling = 54 m
2(P + L) = 54
P + L = 27
p = 27 – L

p x L = 180
(27 – L) x L = 180
27l – L² = 180
L² – 27L + 180 = 0
(L – 15)(L – 12) = 0

L – 15 = 0
L = 15

atau

L – 12 = 0
L = 12

karena ukuran lebar lebih pendek dari panjang, maka lebar taman adalah 12 m

Jawaban D