# Solving Equations and Inequalities Graphically

Using a graphing calculator: LEARN how to change the
viewing window.

Zoom 6: Standard Screen

Graph: y_{1} =x^{3} - 4x^{2} -129x + 396

An appropriate viewing window should show relative max,
relative min, intercepts; or we may

want to zoom in or out to see intersection of lines.

**Graphing a circle**: x^{2} +y^{2} = 9

The graphical solution to: 2x = 6 -x

Algebraic solution gives exact solution, whereas graphing
solution is often an approximations.

Graph:

•Do these lines intersect?

**Solve**: over the
interval [ 1, 6 ].

**Solving equations graphically** x^{2} + 5x + 6 > 0

**Solving equations graphically** x^{3} - 4x^{2}-129x
+ 396 > x^{2}
+ 6x + 125