Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
7. Absolute Value Equations and Inequalities
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Exercise 14 Page 211

How many cases do you have after you remove the absolute value?

Solutions: d=-4 or d=4
Graph:

Practice makes perfect
Before we can solve this equation, we need to isolate the absolute value expression using the Properties of Equality.
5|d|=20
5|d|/5=20/5
|d|=4
An absolute value measures an expression's distance from a midpoint on a number line. |d|= 4

This equation means that the distance is 4, either in the positive direction or the negative direction. |d|= 4 ⇒ ld= 4 d= -4 Both 4 and -4 are solutions to the absolute value equation. Let's graph these solutions on a number line.

To check our solutions, we will substitute them into the equation.
5|d|=20
5| 4|? =20
5(4)? =20
20=20 âś“
Since the substitution resulted in an identity, d=4 is a correct solution.
5|d|=20
5| -4|? =20
5(4)? =20
20=20 âś“
Because the substitution resulted in an identity, d=-4 is also a correct solution.