Write the equation of the axis of symmetry for the following. :) Last time promise. Thanks again?

Question

a. y=x^2 - 6x + 8
b. y= 3x^2 - 4x + 6
Thanks so much. i'm not good at this stuff.

Answer 1

a. y=x^2 - 6x + 8

compare with ax^2+bx+c so a=1, b= - 6, c=8

equation of directrix x = -b/2a = 6 /2 =3

x=3 cuts parabola in axis of symetry put in equation

y=9-18+8= - 1

y+1=0 axis of sym.

b. y= 3x^2 - 4x + 6
a=3, b= - 4
directrix x= - b/2a = 4/6 =2/3

x=2/3 put in 2nd

y = 3*4/9 - 4*2/3 +6

9 y = 12 - 24 +54 = 42

9y-42=0 axis of symetry