### Home > A2C > Chapter 4 > Lesson 4.2.1 > Problem 4-66

4-66.

Remember that the parabola's vertex was

Remember that the only way for a parabola to have only one *x*-intercept is to have the vertex touching the *x*-axis.

To make it so the equation only has one *x*-intercept, you must make the vertex's *y* value equal 0.