ACT Preparation / Unit 11 ACT 1013 short lesson, about 20 seconds
The Parabola
Captions available
The idea
The graph of f(x) = ax² + bx + c is a parabola, opening up when a > 0 and down when a < 0. Its turning point is the vertex, and its y-intercept is c.
In practice
f(x) = −x² + 4 opens down, with vertex (0, 4) and zeros at 2 and −2.
Where people slip
The zeros are the x-intercepts, where f(x) = 0.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
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