Truth and Equations

Truth and Equations

Unit 6 Lesson 2

Poll

The equation a + b =c

could be true or false.

If a is 3, b is 4, and c is 5, is the equation true or false?

• True

• False

Variable

• a letter used to stand in for a number

• Example: x + y = z; when x is 1, y is 2, z is 3

Multiple Select

The equation x ⋅ y = z

could be true or false.

If x is 3, y is 4, and z is 12, is the equation true or false?

• True

• False

An equation

• can be either true or false, and that the truth of an equation with variables depends on the values of the variables. 

• 
  

Coefficient

20x means the same thing as 20 ⋅ x. We will frequently use this notation from now on. 20 is called the coefficient. (The number in front of the variable.)

Multiple Choice

After Elena ran 5 miles on Friday, she had run a total of 20 miles for the week. She ran x miles before Friday.

• x = 20 + 5

• x + 5 = 20

• x+20=5

Multiple Choice

Andre’s school has 20 clubs, which is five times as many as his cousin’s school. His cousin’s school has x clubs.

• 5 ⋅ 20 = x

• 20x = 5

• 5x = 20