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Recap: First Equations

Part of the Fundamentals section of Coddy's Math journey. Lesson 5 of 64.

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Challenge

Solve the equation x - 7 = 15 for x.

Try it yourself

x - 7 = 15

Solve for x

All lessons in Fundamentals

1What an Equation Is

The EquationFinding the UnknownThe Same to Both SidesSolved Means AloneRecap: First Equations

4Two-Step Equations

Two Layers to UndoSubtract, Then DivideAdd, Then DivideA Division InsideNegatives in Two StepsRecap: Two-Step Equations

7Fractions in Equations

A Fraction CoefficientClearing One DenominatorTwo DenominatorsA Fraction Around a SumCross-MultiplyingRecap: Fractions

10From Words to Equations

Phrases into ExpressionsSentences into EquationsConsecutive NumbersAge and MoneyA Perimeter ProblemRecap: Words

2One-Step Equations

Undoing AdditionUndoing SubtractionUndoing MultiplicationUndoing DivisionInverse OperationsRecap: One-Step Equations

5Tidying First

Like TermsTerms and Numbers MixedThe Distributive PropertyDistributing a SubtractionTidy, Then SolveRecap: Tidying First

8Decimals and Percent

Decimal CoefficientsTwo-Step with DecimalsAdding a PercentPercent EquationsRecap: Decimals

11Formulas

Using a FormulaFinding a Missing ValueSolving for a LetterTemperatureRecap: Formulas

3Negative Numbers

Below ZeroA Negative AnswerNegative CoefficientsThe Opposite of xRecap: Negatives

6Variables on Both Sides

x on Both SidesGathering the x'sNumbers and x's EverywhereParentheses on One SideWhen x Is NegativeRecap: Both Sides

9Special Cases

No SolutionAlways TrueChecking a SolutionRecap: Special Cases

12Final Challenges

Parentheses on Both SidesFractions and x'sDecimals on Both SidesThe Story Problem