SOLUTION: How do i solve this? I have tried many different ways, asked tons of people. And no one can figure it out. Find the values for a and k in the function {{ y=ax^2+k}} that conta

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: How do i solve this? I have tried many different ways, asked tons of people. And no one can figure it out. Find the values for a and k in the function {{ y=ax^2+k}} that conta      Log On


   

Question 225879: How do i solve this?
I have tried many different ways, asked tons of people. And no one can figure it out.
Find the values for a and k in the function {{ y=ax^2+k}} that contains the points (2,0) and (4,-6).
Thank you i would really appreciate it.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
y=ax%5E2%2Bk Start with the given equation.


0=a%282%29%5E2%2Bk Plug in x=2 and y=0 from the given point (2,0)


0=4a%2Bk Square 2 to get 4.


-4a=k Subtract 4a from both sides.


So k=-4a


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y=ax%5E2%2Bk Go back to the given equation.


-6=a%284%29%5E2%2Bk Plug in x=4 and y=-6 from the given point (4,-6)


-6=16a%2Bk Square 4 to get 16.


-6=16a-4a Plug in k=-4a


From here, solve for 'a'. Once you have the value of 'a', plug it into k=-4a to find 'k'.