SOLUTION: Use the vertex (h, k) and a point on the graph (x, y) to find the general form of the equation of the quadratic function. (h, k) = (−5, −1), (x, y) = (&#872

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: Use the vertex (h, k) and a point on the graph (x, y) to find the general form of the equation of the quadratic function. (h, k) = (−5, −1), (x, y) = (&#872      Log On


   



Question 1054626: Use the vertex
(h, k)
and a point on the graph
(x, y)
to find the general form of the equation of the quadratic function.
(h, k) = (−5, −1), (x, y) = (−7, 3)
f(x) = ________

Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Some of the description should be changed. Okay to let vertex be (h,k), but for some other given point on the graph, say this is some "given" point of something like (p,v). You do not want to confuse general point (x,y) with any specific point.

That now taken care of, start with Standard Form.
y=m%28x-h%29%5E2%2Bk, for some real number m so that m%3C%3E0.

Your graph for the equation passes through some given point, (p,v).
m%28x-h%29%5E2=y-k
m=%28y-k%29%2F%28x-h%29%5E2

m=%28v-k%29%2F%28p-h%29%5E2-------Now you would "know" value for m.

Put everything back into the standard form.
y=%28%28v-k%29%2F%28p-h%29%5E2%29%28x-h%29%5E2%2Bk
Obviously this is not yet in GENERAL form, but still in fairly standard form. Just do all the needed "simplifications" or multiplications and arrange into general form.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Use the vertex
(h, k)
and a point on the graph
(x, y)
to find the general form of the equation of the quadratic function.
(h, k) = (−5, −1), (x, y) = (−7, 3)
f(x) = ________
Vertex/Standard form: y+=+a%28x+-+h%29%5E2+%2B+k
3+=+a%28-+7+-+-+5%29%5E2+%2B+-+1 ------ Substituting (- 7, 3) for (x, y) and (- 5, - 1) for (h, k)
3+=+a%28-+2%29%5E2+-+1
3+=+4a+-+1
3+%2B+1+=+4a_____4+=+4a______4%2F4+=+a______1 = a
Vertex/Standard form: y+=+%28x+%2B+5%29%5E2+-+1______y+=+x%5E2+%2B+10x+%2B+25+-+1