Question 195593
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a) Find the x intercepts for the parabola y = x2 – 6x + 5. 


Set y=0:
{{{x^2-6x+5=0}}}
{{{(x-5)(x-1)=0}}}
X-Intercepts: {{{red(x=5)}}}; {{{red(x=1)}}}

{{{drawing(300,300,-8,8,-8,8,graph(300,300,-8,8,-8,8,x^2-6x+5),blue(circle(5,0,.18)),blue(circle(1,0,.18)))}}}



b) Find the vertex of the parabola y = - 2x2 + 8x + 4 


By Formula, {{{h=-b/2a}}};where{{{system(a=-2,b=8,c=4)}}}


{{{h=-8/(2*-2)=-8/-4=red(2)}}}
 *Remember {{{h=red(x=2)}}}


Substitute x=2 to our eqn:
{{{y=-2(2)^2+8(2)+4}}}
{{{y=-2(4)+16+4}}}
{{{y=-8+20}}}
{{{red(y=12)}}}


Vertex <font color=blue>(2,12)</font>
{{{drawing(400,400,-5,10,-5,15,grid(1),graph(400,400,-5,10,-5,15,-2x^2+8x+4),green(circle(2,12,.15)))}}}



Thank you,
Jojo</font>