Help with this function will be rewarded: y = 3x^2 – 30x + 5?

Question

Sketch the graph of the function y = 3x^2 – 30x + 5.
What are the domain and range of the function?
What are the x-intercepts? Approximate to two decimal places.

a. domain = [–70, ∞); range = (–∞, ∞);
x-intercepts: points (9.97, 0) and (0.10, 0)

b. domain = (–∞, ∞); range = [–70, ∞);
x-intercepts: none

c. domain = [–70, ∞); range = (–∞, ∞);
x-intercepts: points (9.83, 0) and (0.17, 0)

d. domain = (–∞, ∞); range = [–70, ∞);
x-intercepts: points (9.83, 0) and (0.17, 0)

ANSWERS are above:

Answer 1

answer d is correct

Answer 2

D is the answer. The vertex of the graph is at (5, -70), and the range goes from there to infinity. Those points are the x-intercepts, and the domain is all real numbers. If you don't know what the graph looks like, graph it at http://www.quickmath.com/ .

Answer 3

You don't even need to solve this one.

Look at the possibilities. The domain (range of valied x-values) of this parabola are infinite, so your only two options are b and d.

On both of these options the range is from -70 to positive infinity. A parabola such as this MUST then have x-intercepts; and since only d lists x-intercepts, d must be your answer.

Answer 4

i have formula answerer like this
if your function like this ax^2+bx+c do like this
1)if a>0 so you have some border show like "U"(have up head) and have a head with X=(-b/2a)
2)if 1)if a<0 so you have some border show "n"(have down head) and have a head with X=(-b/2a)
and also in this functions have domain = (–∞, ∞)
so in your problem "b" is answer
b.domain = (–∞, ∞); range = [–70, ∞);
x-intercepts: none

Answer 5

Perhaps this site would help you:

http://www.algebrahelp.com/calculators/equation/

I know I can't! lol