120 likes | 228 Views
Absolute Value Equations. Unit 3, Day 5. Review of Absolute Value. http:// www.brainpop.com/math/numbersandoperations/absolutevalue/preview.weml. 5 units. The absolute-value of a number is that numbers distance from zero on a number line. For example, |–5| = 5. 1. 6. 4. 3. 0. 1.
E N D
Absolute Value Equations Unit 3, Day 5
Review of Absolute Value http://www.brainpop.com/math/numbersandoperations/absolutevalue/preview.weml
5units The absolute-value of a number is that numbers distance from zero on a number line. For example, |–5| = 5. 1 6 4 3 0 1 2 3 4 5 5 2 6 Both 5 and –5 are a distance of 5 units from 0, so both 5 and –5 have an absolute value of 5.
How to Solve Absolute Value Equations: Isolate the absolute-value expression Split the problem into two cases.
Solve the equation. |x| –3 = 4 + 3 +3 |x| = 7 x = 7 –x = 7 –1(–x) = –1(7) x = –7
Solve and check |a| – 3 = 5 |a| – 3 + 3 = 5 + 3Add 3 to each side. |a| = 8 Simplify. a = 8 or a = –8
+2 +2 Solve the equation. |x 2| = 8 x 2= 8 x 2= 8 +2 +2 x = 10 x = 6
Solve |3c – 6| = 9 3c – 6 = 9 3c – 6 = –9
|x + 7| = 8 x + 7 = –8 x + 7 = 8 – 7 –7 – 7 –7 x = –15 x = 1
CAREFUL! Not all absolute-value equations have solutions. If an equation states that an absolute-value is negative, there are no solutions.
Solve the equation. 2 |2x 5| = 7 2 2 |2x 5| = 5 1 1 |2x 5| = 5 Absolute values cannot be negative. This equation has no solution.
Homework p.237, #1-21