SOLUTION: I am having trouble solving: Y= -3x^2-6x-5, I have to graph it, so I need to know the x values, the y values, the x intercepts, the y itercepts and vertex

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: I am having trouble solving: Y= -3x^2-6x-5, I have to graph it, so I need to know the x values, the y values, the x intercepts, the y itercepts and vertex      Log On


   



Question 252391: I am having trouble solving: Y= -3x^2-6x-5, I have to graph it, so I need to know the x values, the y values, the x intercepts, the y itercepts and vertex
Found 2 solutions by richwmiller, edjones:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
y=-3x^2-6x-5
there are no real solutions
it is a parabola facing down
it can't be factored
if x=0 then y=-5
use the quadratic formula to solve
it only crosses the y axis once
it never cross the x axis
the vertex is-1,-2
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case -3x%5E2%2B-6x%2B-5+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-6%29%5E2-4%2A-3%2A-5=-24.

The discriminant -24 is less than zero. That means that there are no solutions among real numbers.

If you are a student of advanced school algebra and are aware about imaginary numbers, read on.


In the field of imaginary numbers, the square root of -24 is + or - sqrt%28+24%29+=+4.89897948556636.

The solution is

Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+-3%2Ax%5E2%2B-6%2Ax%2B-5+%29

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
y= -3x^2-6x-5
.
Use whatever x values you wish and calculate the y values.
.
x intercepts (when y=0)
-3x^2-6x-5=0
There are none. There are no real zeros. Quadratic formula.
.
y intercepts (when x=0)
y=-5
.
vertex at x:
-b/2a
x= -(-6)/2(-3)
=6/-6=-1
at y=-3+6-5=-2
.
graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C-3x%5E2-6x-5%29
.
Ed