Teacher – Mrs. Volynskaya Algebra 2 Absolute Value Equations Absolute value A numbers distance from 0 on number line. ALWAYS POSITIVE!!! Extraneous Solution A solution that appears to be a solution, but doesn’t work in the original equation.
1.5 Interpreting Absolute Value Equations Equation|x| = |x 0| = k MeaningThe distance between x and 0 is __k__. Graph Solutionsx 0 = k or x 0 = k x = _ k_ or x = _k_
1.5 Interpreting Absolute Value Equations Equation|x b| = k MeaningThe distance between x and b is _k_. Graph Solutionsx b = k or x b = k x = _b k_ or x = _b + k_
Teacher – Mrs. Volynskaya Algebra Solving an absolute value equation Use these steps to solve an absolute value equation | ax + b | = c where c > 0. Step 1 Write two equations: ax + b = _c_ or ax + b = _ c__. Step 2 Solve each equation. Step 3 Check each solution in the original _absolute value_ equation.
Example 1 Solve a simple absolute value equation Solve |x 3 | = 6. Graph the solution. x 3 = -6 or x 3 = x = -3 x = 9 These are the values that are 6 from 3 on the number line.
Example 2 Solve an absolute value equation Solve |4x + 10 | = 6x. Check for extraneous solutions. 4x + 10 = 6x or4x + 10 = -6x -4x -4x -4x-4x 10 = 2x10 = -10x 10/2 = 2x/2 10/-10 = -10x/-10 5 = x-1 = x CHECK
Example 2 Solve an absolute value equation Check |4x + 10 | = 6x | 4(_5_) + 10| ≟ 6(_5_) |4( 1_ ) + 10 | ≟ 6(_ 1_) |_30_| ≟ _30_|_6_| ≟ _ 6_ _30_ = _30__6_ _ 6_ X = 5 x = -1 is rejected, because it is an extraneous solution.
1.5 Absolute Value Inequalities InequalityEquivalent Form |ax + b| _<_ c c < ax + b < c Graph of Solution InequalityEquivalent Form |ax + b| _>_ c ax + b c Graph of Solution
Example 3 Solve an inequality Solve |2x + 5 | > 3. Then graph the solution. 2x x -2 2x/2 -2/2 x -1
Example 4 Solve an inequality Solve |x 1.5| 4.5. Then graph the solution. x – 1.5 ≤ 4.5 or x – 1.5 ≥ x ≤ 6 x ≥ -3