1. Variables and Equations

2. An equation is a mathematical sentence with an equal sign
An equation is a mathematical sentence with an equal sign. It can be true, false or an open sentence
examples:
= TRUE because 18 = 18
= FALSE because 24 ≠ 20
5b + 7 = OPEN because b can
stand for any value

3. Determine if the following are true, false or open sentence:
= 29
(6 - 3) – 1 = 3
x = 30
= 25
23 – 7 = 16
3x + 20 = 48

4. A solution of an equation is a value of the variable that makes the equation true
example:
Is 30 a solution of the equation x = 200
170 + x = 200
= Yes, 30 is a
200 = solution
200 = 200

5. Check if the given number is a solution of the equation
20 – c = c = 8
a + 5 = a = - 2
2y + 3 = y = 3
5p – 1 = p = 0
m + 29 = m = - 4