Question 448483
<pre><font face = "Tohoma" size = 4 color = "indigo"><b> 
Hi
y=x^2-9x+18
Note: the vertex form of a parabola, {{{y=a(x-h)^2 +k}}} where(h,k) is the vertex
y=x^2-9x +18   |Completing the square
y = [(x-4.5)^2 - 20.25] +18
y = (x-4.5)^2 - 2.25   Vertex(4.5,-2.25) a = 1 > 0 parabola opens upward
x-intercepts when y = 0 are also the solutions for the quadratic equation
 (x-4.5)^2 = 2.25
    x-4.5 = ± {{{sqrt(2.25)}}}
      {{{x = 4.5 ± 1.5)}}}  x = 6 or x = 3
OR
 x^2 - 9x + 18 = 0  Using Quadratic Formula to solve for x
{{{x = (-b +- sqrt( 9))/(2*a) }}} 
{{{x = 4.5 +- 3/2)}}} 
   x = 4.5 ± 1.5   x = 6 or x = 3
{{{drawing(300,300, -10, 10, -10, 10,  grid(1),
circle(4.5, -2.25,0.4),
circle(6, 0,0.4),
circle(3, 0,0.4),
graph( 300, 300,  -10, 10, -10, 10,0, x^2 - 9x + 18))}}}