A Negative Answer
Part of the Fundamentals section of Coddy's Math journey. Lesson 13 of 64.
x + 5 = 2: a number plus 5 gives 2, so the number must be below zero. The move is the usual one, subtract 5 from both sides:
x + 5 - 5 = 2 - 5
x = -3
Check: -3 + 5 = 2. True.
Do not be put off by a negative result, and do not "fix" it by flipping the sign. If the moves were legal, the answer is right, whatever its sign. When the answer looks strange, substitute it back in: the equation itself will tell you whether it works.
Challenge
Solve the equation x + 8 = 3 for x.
Try it yourself
x + 8 = 3
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