A quadratic graphs as a parabola, and its vertex is the turning point. A positive coefficient on makes that point the bottom of the curve, so graph the function in Desmos and click its minimum. Read the horizontal coordinate, not the lowest output or a point where the graph crosses an axis.
Hints
- Hint 1
The vertex is where a parabola turns. A positive coefficient on makes the curve open upward. Which point is its lowest point?
- Hint 2
An ordered pair puts the horizontal coordinate first and the vertical coordinate second. After you click Desmos's lowest marked point, which coordinate gives its position along the -axis?
Step-by-step
Graph and click the vertex
Step 1Identify the point you need
The coefficient of is , so the graph is an upward-opening parabola, a U-shaped curve. Its vertex, where it turns, is its lowest point.
- Step 2
Read the vertex's horizontal coordinate
Type in Desmos. Click the curve, then its marked lowest point. Desmos labels it . The first coordinate gives the horizontal position. The is the minimum output, not the requested coordinate. The vertex's -coordinate is . Grid in 1.