Question

For which value of m does the graph of y = 18x2 + mx + 2 have exactly one x-intercept?

Answer 1

Answer:

m = +/- 12

Step-by-step explanation:

A quadratic function has only one x-intercept when the discriminant is equal to 0. The discriminant is b^2 - 4(a)(c).

When we plug in what we know, we have:

m^2 - 4(18)(2) = 0.

Then using algebraic properties, solve for m.

m^2 - 144 = 0

m^2 = 144

m = +/- 12

When you plug in positive or negative 12, and then factor you will see that it comes out to a difference of squares, proving that there is only one x-intercept.