Question 1709
quadratics are symmetric about the minimum or maximum point...their shape is either a U-shape (for a positive x^2 term) or is n-shaped (for a negative x^2 term).

The beauty and ease of finding a quadratic is "fun".

just pick some "obvious" points...like

1. when x=0, then y=-5
2. when y=0, then {{{x^2=5}}}, so x HAS 2 SOLUTIONS....+{{{sqrt(5)}}} and -{{{sqrt(5)}}}.

So, we can instantly sketch the graph, and as the curve crosses the x-axis at the "same" point on both side of the y-axis, then it is a symmetric shape on the y-axis...so, the minimum point is at y=-5

{{{graph(300,200,-3, 3, -6, 4, (x^2-5))}}}

cheers
Jon.