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Well first we find the vertex, which is located at:

(-b/(2a),P(-b/(2a)))

Since b is -1 and a is 1, we're left with:
(1/2, -25/4)


Now we need to find the zeroes:
(-b +/- sqrt(b2-4ac))/(2a)

(1 +/- sqrt(25))/(2) = (3, 0) and (-2, 0)


Optional:
Y-intercept:
P(0) = -6
(0, -6)


Plot all 3 (or 4) points on a graph and draw a parabola through them.