8.3 Graphing quadratic inequalities in two variables
Graphing quadratic inequalities in two variables
Grab a pen and grid paper for this lesson. We will learn the tricks on graphing quadratic inequalities in two variables.
Basic concepts:
 Quadratic function in general form: y = $ax^2 + bx+c$
 Quadratic function in vertex form: y = $a(xp)^2 + q$
 Graphing parabolas for given quadratic functions
 Solving quadratic inequalities
Related concepts:
 Solving absolute value inequalities
Lessons

a)
$y = \frac{1}{3}{x^2}  \frac{2}{3}x  \frac{8}{3}$

b)
$y \ge \frac{1}{3}{x^2}  \frac{2}{3}x  \frac{8}{3}$

c)
$y$ < $\frac{1}{3}{x^2}  \frac{2}{3}x  \frac{8}{3}$


a)
$y =  {x^2}  4x$

b)
$y$ > $ {x^2}  4x$

c)
$y \le  {x^2}  4x$
