Undoing Division
Part of the Fundamentals section of Coddy's Algebra journey. Lesson 9 of 64.
x/4 means x divided by 4. It is written as a fraction with x on top. In x/4 = 5 the unknown is divided by 4, and the result is 5. To undo the division, multiply both sides by 4:
x/4 × 4 = 5 × 4
x = 20
On the left, dividing by 4 and then multiplying by 4 cancel out, so x is alone. On the right, 5 × 4 = 20. Check by substituting: 20/4 = 5 is true. Whenever the unknown is divided by a number, multiplying both sides by that number clears the fraction.
Challenge
EasySolve the equation x/3 = 8 for x.
Try it yourself
Solve for x
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Fundamentals
1What an Equation Is
The EquationFinding the UnknownThe Same to Both SidesSolved Means AloneRecap: First Equations4Two-Step Equations
Two Layers to UndoSubtract, Then DivideAdd, Then DivideA Division InsideNegatives in Two StepsRecap: Two-Step Equations2One-Step Equations
Undoing AdditionUndoing SubtractionUndoing MultiplicationUndoing DivisionInverse OperationsRecap: One-Step Equations5Tidying First
Like TermsTerms and Numbers MixedThe Distributive PropertyDistributing a SubtractionTidy, Then SolveRecap: Tidying First