PRE-Algebra Rules
List the four symbols for multiplication:
x
*
( )
.
x + 20 = 25
x = 5
What is the difference between an expression and an equation?
equations have an equal sign
expression do not
What does the E stand for in P.E.M.D.A.S
x= 8
2x + 10 = ?
26
True or False
When solving for X (or any variable), I need to get X by itself.
EX. 3+ x =12
True
What is a varible?
A placeholder for any number, a symbol. Typically a letter
5(4 +5) = x
x = 45
True or False
I can combine terms even when they don't have a variable next to them.
Ex. is 2x +3 the same as 5x?
FALSE
Only combine terms with the same variable or no variable
2x +3 is NOT 5x
correct: 2x+ 3x = 5x
How do I move terms (numbers) from one side of the equation to the other?
Ex. 5x + 3 = 28
5x ? = 28 - 3
5x = 25
do the opposite operation
In the example, subtract 3
5(x) + 10 = 30- 10
X=2
What step happened next?
3x- 3 = 7
3x = 10
Add 3
You need to add 3 to cancel -3 and add 3 to the other side of the equation, 7 +3 = 10
What is the hidden operation between 5y? Bonus points if you can list all 4.
Multiplication:
5 * y
5 (y)
5 x y
5 . y
15 - 10 + 5 = x
x=0
What step happened to x = 4 that made it 3x= 12?
x=4
3x = 12
multiply both sides by 3