Menu

A Negative Answer

Part of the Fundamentals section of Coddy's Algebra journey. Lesson 10 of 61.

An equation can have a negative solution. In $x+5 = 2$ , a number plus 5 gives 2, so the number must be less than zero. Solve it the usual way. Subtract 5 from both sides:

$x+5-5 = 2-5$

$x = -3$

Check the answer in the original equation: $-3+5 = 2$ , which is true.

An equation can have a negative solution. Keep the sign you get from solving. Then substitute the answer into the original equation to check that both sides are equal.

Challenge

Easy

Solve the equation $x+8 = 3$ for $x$ .

Try it yourself

x+8 = 3

Get $x$ alone

All lessons in Fundamentals

1What an Equation Is

The Equation The Same to Both Sides Undoing Subtraction Recap: First Equations

4Two-Step Equations

Two Layers to Undo Subtract, Then Divide Add, Then Divide A Division Inside Negatives in Two Steps Recap: Two-Step Equations

7Fractions in Equations

A Fraction Coefficient Clearing One Denominator Two Denominators A Fraction Around a Sum Cross-Multiplying Recap: Fractions

10From Words to Equations

Phrases into Expressions Sentences into Equations Consecutive Numbers Age and Money A Perimeter Problem Recap: Words

3Negative Numbers

Below ZeroA Negative AnswerNegative Coefficients The Opposite of x Recap: Negatives

6Variables on Both Sides

x on Both Sides Gathering the x's Numbers and x's Everywhere Parentheses on One Side When x Is Negative Recap: Both Sides

9Special Cases

No Solution Always True Checking a Solution Recap: Special Cases

12Final Challenges

Parentheses on Both Sides Fractions and x's Decimals on Both Sides The Story Problem