SAT Math / High Yield Lessons
Read a parabola’s vertex, its x-intercepts, or its y-intercept from the form the SAT prints, and pick the equivalent form that shows the feature a question asks for.
The parabola y equals (x minus 1) squared minus 4 is drawn, and its lowest point, (1, negative 4), lights up, because a square is never negative and x minus 1 is 0 when x is 1. The same parabola is written as y equals (x plus 1)(x minus 3), and its x-axis crossings at negative 1 and 3 light up. Multiplied out, it is y equals x squared minus 2x minus 3, and its y-axis crossing at negative 3 lights up. Next, a question asks what a different parabola will do if a goes from 1 to negative 1, and the prediction flip to open downward is picked. Dragging the a slider to negative 1 flips the parabola about its vertex, (1, 2), and the prediction is marked right. Finally, answer where the graph of y equals (x plus 3)(x minus 5) crosses the x-axis, using the buttons after the picture.
