National Parks
National Monuments
National Historical Parks, Memorials, and Battlefields
National Recreation Areas, Seashores and Trails
Other Preserves and Protected Areas
... + \frac{c}{a}=0 </math> which is equivalent to <math>x^2+\frac{b}{a}x=-\frac{c}{a}.</math> The equation is now in a form in which we ca ...