Chapter 1 Section 5

Solving Equations and Inequalities Graphically
Zoom→trap the x-intercept.
 

Absolute Value
Solve |2x-4| = 8 algebraically
2x-4=8    or    2x-4= -8
x = 5    or    x = -2

Relation between Intervals and Absolute Value
|a| < D if -D<a<D
|a| > D if a < -D or a > D