June 20th
June 20th
Solving Quadratic Inequalities
You will be able to:
1. Identify quadratic inequalities in one variable.
2. Solve quadratic inequalities graphically
Standard Form for a Quadratic Inequality in One
Variable:
ax + bx + c < 0
ax + bx + c > 0
ax + bx + c  0
ax + bx + c  0
To solve quadratic equations graphically:
• Graph both parabolas on the same coordinate plane.
• Determine the intersections, if they exist.
• Locate the portion of the y 1 graph below
the y 2 graph if the inequality is “less
than.” Locate the portion of the y 1 graph above
the y 2 graph if the inequality is “greater
than.”
• Determine the x -coordinates for this portion of the
graph.
- If the portion is to the left of the intersection, then
x is less than the x -coordinate of the intersection.
- If the portion is to the right of the intersection, then
x is greater than the x -coordinate of the intersection.
- If the portion is between the left and right
intersections, then x is greater than the x -coordinate
of the left intersection and less than the x -coordinate
of the right intersection.
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