Algebra Equations What you’ll learn in this section:

Solving equations using mental math.

New VocabularyDefining the variable: choosing a variable to

represent the unknown in a problem.Inverse operations: operations that “undo” each

other. Addition and subtraction are inverse operations.

New VocabularyEquation: a sentence in mathematics that

contains an equal sign.Solution: a number that makes a sentence true.

Solving an equation: the process of finding a solution to an equation.

Solve the Equation Mentally

Solve 16 + m = 28

Solution is 12

Solve Mentally

1. c - 10 = 20 2. 12 = y + 8

3. 7n = 49

Algebra EquationsSubtraction Equation of Equality:

If you subtract the same number from both sides of the equation, the two sides

remain equal.

Solving Addition and Subtraction Equations

Write the equationx + 4 = 9

Solving Addition and Subtraction Equations

Solvex + 4 = 9

-4 - 4

Subtract 4 from both sides of the equation

Solving Addition and Subtraction Equations

Solvex + 4 = 9

-4 - 4 x = 5

The solution is 5.

Simplify

Algebra EquationsAddition Property of Equality:

If you add the same number to both sides of an equation, the two sides remain

equal.

Algebra Equations

Write the equationx – 13 = 25

Algebra Equations

x – 13 = 25 + 13 + 13 Add 13 to

both sides of the equation

Algebra Equations

x – 13 = 25 + 13 + 13

x = 12

The solution is x = 12

Simplify

Algebra EquationsYour Turn

You must show your work on these problems even if you can solve them in

your head! 1. m + 15 = 34

2. n – 12 = 163. d + 10 = 454. c – 8 = 14

Algebra EquationsYour Turn

You must show your work on these problems even if you can solve them in

your head! 1. m + 15 = 34 m=19

2. n – 12 = 16 n = 283. d + 10 = 45 d = 35 4. c – 8 = 14 c = 22