A variable is an unknown quantity. For example:
3 + ? = 10
What goes in the box?
7
3 + 7 = 10
10 = 10
X=
Think of x as being a jar of jelly beans.
We don’t know how many jelly beans are in the jar, so we give it a name, x.
So, 4x =
Suppose that there are 300 jelly beans in each jar, then x = 300.
How many would be in 4 jars?
X = 300
300
We have 4 x’s , so 4(300) =1200
300
300
300
300
Find the area of the rectangle.
Remember: Area = length * width
Area = length * width
Area = (x+2) * 3
AREA = 3 ( x + 2 )
3(x+2)
3(x) +
3(2)
3x + 6
Terms: -x , 2x, 8
Coefficients: -1 , 2
Constant Term: 8
Like Terms: -x , 2x
How many chickens? 3
How many Horses?
How many pigs?
2
1
3x  3 y  5z  6 x  2 z  5 y
2
(3 x  6 x )  (3 y )  ( 2 z  5 z )  5 y
9x
3y
7z
5y
2
2
Pg. 99-100
5-40