Answer:
0
Step-by-step explanation:
When there is one x-intercept, the discriminant is zero.
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The discriminant is used to compute the difference between the roots. When it is positive, the real roots are different, so there are two x-intercepts.
When the discriminant is zero, there is no difference between the roots, so there is one x-intercept (as here).
When the discriminant is negative, there are no x-intercepts and the two roots are complex.