Brackets and a Flip
Part of the Inequalities & Absolute Value section of Coddy's Algebra journey. Lesson 57 of 61.
A longer inequality is solved with the same steps as a short one, done one after another. Take . Open the bracket, collect the terms on the left and the numbers on the right, then divide. The coefficient left in front of is negative, so the last division flips the sign.
You can also collect the terms on the right, toward the . Then the coefficient is positive and there is no flip. You end with , which reads as . Both ways give the same answer. One way has a flip and the other has a swap of sides at the end. No way has both.
Before you start, count the parts of the inequality: a bracket, terms on both sides, numbers on both sides. Then you need four steps: open the bracket, collect the terms, collect the numbers, and divide. At each step, ask whether it flips the sign. Only multiplying or dividing by a negative number does.
Challenge
HardSolve the inequality for .
Try it yourself
Get alone on one side
All lessons in Inequalities & Absolute Value
1What an Inequality Is
The Four SignsA Picture on a LineReading It BackwardsRecap: What an Inequality Is4Two-Step Inequalities
Two StepsSubtract, Then FlipWith a FractionA Bracket on the WayRecap: Two-Step Inequalities5Variables 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 Solutions9Absolute Value Equations
Distance from ZeroThe Equation |x| = 3Distance from a PointIsolate the Bars FirstA Coefficient InsideNo Solution, One SolutionRecap: Absolute Equations12Final Challenges
Brackets and a FlipA Chain with a FlipA Wide Absolute ValueOutside, with a FractionThe Picture at the End