Parentheses on One Side
Part of the Fundamentals section of Coddy's Math journey. Lesson 32 of 64.
3(x + 2) = 2x + 10: open the bracket first, then gather.
3x + 6 = 2x + 10
x + 6 = 10
x = 4
Check: 3(4 + 2) = 18 and 2 × 4 + 10 = 18.
Distributing before gathering is not optional here: while the x is inside a bracket, subtracting 2x from both sides leaves 3(x + 2) - 2x, which is no tidier. Open brackets, collect on each side, then gather across the equals sign. That order handles every linear equation you will meet.
Challenge
Solve the equation 2(x + 5) = x + 13 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