use blue for quadratic term, hotpink is indistinguishable from red
use blue for quadratic term, hotpink is indistinguishable from red

Signed-off-by: Chris Malley <74b2712074b149d140079dbd7e875955d192e617@pixelzoom.com>

phetsims/graphing-quadratics,phetsims/graphing-quadratics,phetsims/graphing-quadratics