|
Question 431081: describe the graph of y= -2x^2-6x+5. tell me everything you can about the graph.
Found 3 solutions by Gogonati, solver91311, ewatrrr:
Answer by Gogonati(855)   (Show Source):
Answer by solver91311(24713)  (Show Source):
You can put this solution on YOUR website!
It it is a quadratic in x, so it is a parabola with a vertical axis of symmetry.
The lead coefficient is negative, so it opens downward.
The constant term is 5, so the y-intercept is (0,5)
The opposite of the first degree term is 6, divided by 2 times the lead coefficient, is  . So the x-coordinate of the vertex is . Substitute for x and then do the arithmetic to calculate the y-coordinate of the vertex.
By symmetry, there is a function value of 5 a distance of horizontally from the vertex, hence (-3,5) is a point on the graph.
Use the discriminant to determine the nature of the zeros.
If there are 1 or 2 real zeros, use the quadratic formula to determine the x-coordinates of the x-intercepts.
John
My calculator said it, I believe it, that settles it
Answer by ewatrrr(24785)  (Show Source):
You can put this solution on YOUR website!
Hi
y= -2x^2-6x+5
1)parabola opening downward
y=-2(x+3/2)^2 +19/2
2) vertex Pt(-1.5,9.5)
3) cross the y-axis at Pt(0,9.5)
4) Axis of symmetry is x = -1.5
5) 9.5 is the maximum value of y when x = 1.5
6) x = -3/2 ħsqrt(4.75) are the solutions | (x+3/2) = ħsqrt(19/4)
7) x-intercepts are (.679,0) and (-3.68,0)
|
|
|
| |
