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numbers and algebraic expressions
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trigonometry
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combinatorics
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elements of statistics
kropki game

The graph of a quadratic function is parabola. The position of a graph to x-axis depend on the delta and "a". y = ax^2+bx+c The formulas for coordinates of the vertex W(x_w, y_w) of parabola: x_w = -b/2a, y_w = -Δ/4a. The vertex coordinates of a parabola are easly get from the vertex form. x_w = p, y_w = q. Examples.