Function question help with brief explanation

Question

Given the function below, what is the value of the discriminant, and how many times does the graph of this function intersect or touch the x-axis?

F(x) = 4x^2 6x - 5

Answer 1

It looks as though you're missing a sign in the equation, although the answer does not change regardless. You have to look at the equation in the format ax^2 + bx + c.

Following this:

a = 4

b = +/- 6, depending on the sign between ax^2 and bx

c = -5

The discriminant of the equation is b^2 - 4ac.

Regardless of the sign of b, squaring gives 36, and 36 - (4*4*-5) = 116. So the discriminant of your problem is 116, regardless of the missing sign.

As for the zeros of the equation (where it intersects or touches the x-axis), the simple answer is twice. This can be found simply using a graphing calculator. If you are interested in doing it longhand without graphing the equation (which could also work), you can learn the method at the following link:

http://fym.la.asu.edu/~tturner/MAT_117_o...