SOLUTION: Hello again! I really need help with this problem. Could someone kindly help me? The class is working with Quadratic functions and graphs – I'm supposed to find the vertex and

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Question 18492: Hello again!
I really need help with this problem. Could someone kindly help me?
The class is working with Quadratic functions and graphs – I'm supposed to find the vertex and intercepts , then sketch its graph. l really need help.
y= -x^2 + 2x + 3
This is a head-scratcher for me. Thanks for all of the help. It is appreciated.

Answer by Alwayscheerful(414) About Me  (Show Source):
You can put this solution on YOUR website!
Hi
I reccomend finding the vertex first, then the intercepts, then finally graph it. You can find the vertex using vertex form:
y-k=a%28x-h%29%5E2
(h,k) is your vertex
If you don't like doing a lot of math, here is a short cut
h=-b%2F2a
Standard form for quadratic equations: ax%5E2%2Bbx%2Bc=0
That gives you your X value of the vertex.
h=-2%2F2%2A-1
h=1
To find the Y value, plug 1 into the X value in the original equation
%28-1%29%5E2%2B2%281%29%2B3
1%2B2%2B3=6
Your vertex is (1,6)
X and Y-INTERCEPTS
The Y-intercept is always the number without a variable. So, in this question it is 3
There will be 2 X-intercepts.
I will factor this equation to find them.
%28x%2B1%29%28-x%2B3%29=0
To make this equation 0, the X must be -1 or 3
So you X-intercepts are (-1,0) and (3,0)
GRAPH
First graph the vertex (1,6)
Graph the X-Intercepts (-1,0) and (3,0)
Graph the Y-Intercept (0,3)
Your graph should look like this:
graph%28300%2C200%2C-5%2C5%2C-5%2C5%2C-x%5E2%2B2x%2B3%29
Hope this helps!