Equation Vocabulary

Warm-Up

2(1 + 6x)

Find the surface area of a cube where the side (s) is 5 cm. Surface area= 6s2

Important Vocabulary!!

Equation A math sentence that contains an equal sign. It consists of 2 expressions, one on each side of the equal sign.

Examples:

5x + 3 = 18; x ÷ 10 = 12

Important Vocabulary!!

Inverse Operations

Two operations that are opposites so they cancel each other out. They “undo” each other!

What are the inverse operations?

Addition and subtraction

Multiplication and division

How does it work? x + 5 - 5

All you would be left with is x because the inverse operations

cancel each other out.

Important Vocabulary!!

Properties of Equality

When both sides of an equation have the same number added, subtracted, multiplied, or divided, the remaining expressions are still equal.

How do the properties of

equality work? x + 3 = 9

You can use the inverse operation of addition (subtraction) on both sides.

x + 3 = 9 -3 -3

If you take away the same number from both sides, then they would

still be equal.

Important Vocabulary!!

Solution

The set of all values or a single value that make an equation true.

How do you write solutions?

You put the variable from the equation,

then an equal sign, and finally put

what the variable equals.

Example: x = 5; y = 18

Important Vocabulary!!

Reciprocal

When you flip the numerator and denominator of a fraction

Examples:

3/4 to 4/3 and 5/6 to 6/5

Warm-Up

A bottle of puppy medicine says to give 3 mL for every pound of body weight. How much would you give a 15 lb. puppy?

Amy wants to buy some CD’s that are 11.99 each. She has $74.90. How many CDs can she buy?

Substituting into Equations

You will just replace the variable with the given value

Then you will determine whether or not it is a solution to the equation

If it is a solution, then both sides of the equation will be equal!

Learnzillion

http://learnzillion.com/lessons/2514-understand-that-equations-have-one-solution-using-a-pan-balance

Practice

• Determine if the given values make the equation true.

• 86 + x = 102 for x = 16

• 18 + x = 26 for x = 4

• x + 46 = 214 for x = 168

• 9 + x = 35 for x = 26

More Practice

Which of the following values will make the equation true?

x=9, x=12, x=15, x=18

x + 3 = x – 66 3

x = 15

Just one more…

Which of the following values will make the equation true?

y=4, y=5, y=6, y=7

3y + 4 = 4y – 85 4

y = 7