tolong pake caranya yaa

f(x) = x^2 - bx + 7
Ordinat puncak = -8 => y = -8
D/(-4a) = -8
D = 32a
b^2 - 4ac = 32a
(-b)^2 - 4(1)(7) = 32(1)
b^2 - 28 = 32
b^2 = 60
b = √60
Sumbu simetri x = -b/2a = -(-b)/2(1) = b/2 = √60 / 2 = 2√15 / 2 = √15

f(x) = x^2 - bx + 7

y = -8

a = 1
b = -b
c = 7

y = - D/4a
y = - (b^2 - 4ac)/4a
-8 = -((-b)^2 -4(1)(7))/4(1)
-8 = -(b^2 - 28)/4
-b^2 + 28 = -8 × 4
-b^2 + 28 = -32
b^2 = 28 + 32
b^2 = 60
b = akar 60
b = akar (4 × 15)
b = 2 akar 15

Sumbu simetri = -b/2a
Sumbu simetri = -(-b)/2(1)
Sumbu simetri = b/2
Sumbu simetri = (2 akar 15)/2
Sumbu simetri = akar 15