persamaan kuadrat

no. 4

2x² - 3x - 1 = 0

p + q = -b/a = -(-3)/2 = 3/2

pq = c/a = -1/2

akar PK baru :

m = 2p - 1

n = 2q - 1

m + n = (2p - 1) + (2q - 1)

m + n = 2p + 2q - 2

m + n = 2(p + q) - 2

m + n = 2(3/2) - 2

m + n = 3 - 2

m + n = 1

mn = (2p - 1)(2q - 1)

mn = 4pq - 2(p + q) + 1

mn = 4(-1/2) - 2(3/2) + 1

mn = -2 - 3 + 1

mn = -4

PK baru :

x² - (m + n)x + mn = 0

x² - x - 4 = 0

no. 5

Puncak (-2,1)

y = a(x - xp)² + yp

y = a(x + 2)² + 1

melalui A(4,5)

5 = a(4 + 2)² + 1

4 = 36a

a = 4/36

a = 1/9

PK :

y = 1/9 (x + 2)² + 1