SOLUTION: help on this graph needed, please! For the quadratic function y= f(x)= x^2-2x-15, find the vertex and x and y intercepts. Sketch the graph, and state the domain and range. tha

Question 60013: help on this graph needed, please!
For the quadratic function y= f(x)= x^2-2x-15, find the vertex and x and y intercepts. Sketch the graph, and state the domain and range.
thanks again, carol
Answer by funmath(2933) (Show Source): You can put this solution on YOUR website!
Hi Carol,
:
For the quadratic function y= f(x)= x^2-2x-15, find the vertex and x and y intercepts. Sketch the graph, and state the domain and range.
:
You can find the x coordinate of the vertex of a parabola when the quadratic equation is in the form of , with the formula
Your a=1, b=-2, and c=-15

You can find the y coordinate by letting x=1 and solving for y.

The vertex is (1,-16)
:
You can find the x-intercepts, if there are any, by letting y=0 and solve for x. This time you can factor, sometimes you have to use the quadratic formula.

0=(x-5)(x+3)
x-5=0 and x+3=0
x-5+5=0+5 and x+3-3=0-3
x=5 and x=-3
The x intercepts are (-3,0) and (5,0)
:
You can find the y-intercept by letting x=0:

The y-intercept is (0,-15)
The graph looks like this:

Happy Calculating!!!
RELATED QUESTIONS
Please help me solve the following quadratic equation. Find the vertex and intercepts for (answered by stanbon)

Really stuck on this one! For the quadratic function y =F(x) = x^2-2x-15 i need the... (answered by Edwin McCravy)

Please help me find the vertex and intercepts for this quadratic function, and sketch its (answered by venugopalramana)

Please help me find the vertex and intercepts for this quadratic function, and help me to (answered by venugopalramana)

(a) Express the quadratic function in standard form. (b) Find its vertex and its x and y (answered by stanbon)

Please help. Find the vertex and graph the quadratic function y =f(x)=6x^2-x-2 Thank... (answered by stanbon)

Please help me find the vertex and intercepts for this quadratic function, and sketch its (answered by venugopalramana,Earlsdon)

I need help finding the y-incept and the vertex for this quadratic function... (answered by ikleyn)