Question 367357: Hi there, I have to find the quadratic equation that has vertex (-1, -3) and y-intercept (0, -1).
I plugged the vertex into the vertex form and got
Then I plugged in the given y-intercept and solved for a
So my vertex form will be  . Converting this to general form...
Did I do this correctly? I've never seen a problem like this and couldn't find an example in the book. Thanks for your time and have a good evening :)
Found 2 solutions by jim_thompson5910, edjones:
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! You have the correct answer. Good job.
A simple graph will confirm your answer.
Graph of
Notice how it has a vertex of (-1,-3) and a y-intercept of (0,-1)
Answer by edjones(8007)  (Show Source):
You can put this solution on YOUR website! vertex (-1, -3) and y-intercept (0, -1).
y=a(x-h)^2+k vertex point=(h,k)=(-1,-3)
=a(x+1)^2-3
-1=a(0+1)^2-3
-1=a-3
a=2
y=2(x+1)^2-3
=2(x^2+2x+1)-3
=2x^2+4x+2-3
=2x^2+4x-1
.
You did it correctly.
.
Ed
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