Isolate, Then Split
Part of the Inequalities & Absolute Value section of Coddy's Algebra journey. Lesson 52 of 64.
As with equations, the absolute value must be alone before you split. In 2|x| + 1 > 7, subtract 1 from both sides, divide both sides by 2, and only then split.
2|x| > 6
|x| > 3
Now split into two cases: x > 3 or x < -3.
The same goes for a "less than". In |x - 3| - 1 <= 1, add 1 to both sides first to get |x - 3| <= 2. Then write the chain -2 <= x - 3 <= 2 and add 3 to all three parts, so 1 <= x <= 5. The order is: isolate the absolute value, decide whether it is a "less than" (a chain) or a "greater than" (an "or"), split, then solve.
Challenge
MediumSolve |x + 1| - 2 <= 2.
Try it yourself
Solve for x
This lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Inequalities & Absolute Value
1What an Inequality Is
The Four SignsA Picture on a LineClosed or OpenReading It BackwardsRecap: What an Inequality Is4Two-Step Inequalities
Two StepsSubtract, Then FlipWith a FractionA Bracket on the WayRecap: Two-Step Inequalities7Between Two Numbers
Two Conditions at OnceSolving a ChainTwo Moves on All PartsWhen the Chain FlipsChains with FractionsRecap: Between Two Numbers10Absolute Value Inequalities
Less Than: BetweenBetween, ShiftedGreater Than: OutsideOutside, ShiftedIsolate, Then SplitAlways or NeverRecap: Absolute Inequalities2Adding and Subtracting
Add to Both SidesSubtract from Both SidesNegatives in the MixSolve, Then DrawRecap: Adding and Subtracting5Variables on Both Sides
x on Both SidesGather Toward the LargerBrackets FirstAlways True, Never TrueRecap: Variables on Both Sides11From Words to Inequalities
At Least, At MostMore ThanA Budget That ShrinksTwo LimitsRecap: From Words3Multiplying and Dividing
Divide by a PositiveMultiply by a PositiveThe FlipDividing by a NegativeNegative FractionsRecap: Multiply and Divide6Graphing Solutions
From Inequality to PictureIs the Endpoint In?A Flip on the LineRecap: Graphing Solutions