The Equation
Part of the Fundamentals section of Coddy's Algebra journey. Lesson 1 of 64.
An equation says that two things are equal. 3 + 4 = 7 is an equation. The left side and the right side are the same number, 7. The equals sign does not tell you to work something out. It says that both sides are equal.
Most equations have a letter in them. The letter stands for a number you do not know yet, and it is called the unknown. x + 3 = 8 says that some number plus 3 is 8. A number that makes the equation true is a solution. Here 5 is a solution, because 5 + 3 = 8 is true. 4 is not a solution, because 4 + 3 = 8 is false.
An equation is solved when the unknown is alone on one side and its value is on the other side:
x = 5
Every equation in this course is solved when it looks like this. It says that the number is 5.
Challenge
EasyThis equation is already solved. It says that the number is 5.
Press Check to confirm it.
Try it yourself
Solve for x
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