Undoing Multiplication
Part of the Fundamentals section of Coddy's Math journey. Lesson 8 of 64.
A number written next to a letter multiplies it: 3x means "3 times x", and the 3 is called the coefficient. In 3x = 12 the unknown has been tripled, so the inverse move is to divide both sides by 3:
3x/3 = 12/3
x = 4
Dividing 3x by 3 gives 1x, which is just x: the coefficient 1 is never written. Multiplication and division are the second inverse pair; between them and the first pair, every one-step equation is covered.
Challenge
Solve the equation 5x = 35 for x.
Try it yourself
5x = 35
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