Numbers and x's Everywhere
Part of the Fundamentals section of Coddy's Algebra journey. Lesson 31 of 64.
7x - 4 = 3x + 8 has x-terms on both sides and numbers on both sides. Subtract 3x from both sides, add 4 to both sides, then divide by 4.
4x - 4 = 8
4x = 12
x = 3
Check: 7 × 3 - 4 = 17 and 3 × 3 + 8 = 17.
There are three steps, and the order of the first two does not matter. You can collect the numbers first and the x-terms second. What matters is the shape you are aiming for: x-terms on one side, numbers on the other. From that shape, one division gives the solution.
Challenge
MediumSolve the equation 8x - 3 = 5x + 12 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 First6Variables on Both Sides
x on Both SidesGathering the x'sNumbers and x's EverywhereParentheses on One SideWhen x Is NegativeRecap: Both Sides