Quadratic X-Intercepts
An x-intercept is the x-coordinate of the point where a graph intersects the x-axis (also the y = 0 line). Graphs of quadratic equations can have two, one, or no x-intercepts.
To find the x-intercepts of a quadratic equation f(x) = ax2 + bx + c,
1. Set the equation to zero. 0 = ax2 + bx + c 2. Use factoring or the quadratic formula to solve for x.
Example 1: Factoring
Find the x-intercepts of each function. Separate multiple answers by commas. Example: x=-3/2,2If there is no x-intercept, write "none". f(x) = x2 + 7x + 12 x-intercepts: Set the equation equal to zero and factor. x2 + 7x + 12 = 0 (x + 3)(x + 4) = 0 Solve for x. x + 3 = 0 x + 4 = 0 x = -3 x = -4 Therefore, the x-intercepts are -3 and -4. x-intercepts:
Set the equation equal to zero and factor.
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