SOLUTION: Find the equation of quadratic function that has the given vertex and given point. Vertex (1,3) passing through (4,8) Welp,I keep trying and redo-ing the problem, but I don't

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the equation of quadratic function that has the given vertex and given point. Vertex (1,3) passing through (4,8) Welp,I keep trying and redo-ing the problem, but I don't      Log On


   



Question 473484: Find the equation of quadratic function that has the given vertex and given point.
Vertex (1,3) passing through (4,8)
Welp,I keep trying and redo-ing the problem, but I don't think I'm coming out with correct answer .

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find the equation of quadratic function that has the given vertex and given point.
Vertex (1,3) passing through (4,8)
**
What we have here is a parabola of standard form: y=A(x-h)^2+k, with (h,k) being the (x,y) coordinates of the vertex. A is a multiplier which affects the steepness of the curve.
For given problem:
y=A(x-1)^2+3
Using (x,y) coordinates of given point (4,8) to solve for A
8=A(4-1)^2+3
8-3=A(3)^2
5=9A
A=5/9
..
Equation:
y=(5/9)(x-1)^2+3
see graph below as a visual check on answer:
..
+graph%28+300%2C+300%2C+-10%2C+10%2C+-10%2C+10%2C+%285%2F9%29%28x-1%29%5E2%2B3%29+