Question

Where does the graph of y = 2x2 − x − 3 cross the x-axis?

Answer 1

Crossing the x-Axis means

\[f(x)=0\ \\
\therefore 2x^2-x-3 = 0 \]

Which is the characteristic quadratic equation.

\[ \frac{-b \pm \sqrt{D}}{2a} \]
with \[D= b^2-4ac\]

Answer 2

so what is b, a and c?

Answer 3

The characteristic quadratic equation looks like this:

\[ f(x)=ax^2+bx+c\]
so in your case
\[a=2, b=-1, c=-3\]

Answer 4

alright thank you!