Math 7 (Period 4)

Dividing Integers  3.6 cont'd

Averages
Adding  all the number and dividing by the number of items

Make sure that if ZERO is one of the items that you COUNT it as an item!!

Multiplying and Dividing with VARIABLES, INTEGERS, and POWERS

Always plug in a negative number in ( )

Powers of Negative Numbers

The ODD/EVEN Rule

If there is a negative inside parentheses:

Odd number of negative signs or odd power = negative

Even number of negative signs or even power = positive

 Examples

(-2)⁵ = (-2)(-2)(-2)(-2)(-2) = -32

(-2)⁴ = (-2)(-2)(-2)(-2) =  16

If there is a negative BUT no (parenetheses) --> it is always negative

-2⁵ = -32

-2⁴ = -16

So NOW you know why

(-2)⁴  ≠  -2⁴

Again whenever you plug a Negative for a variable ALWAYS put the negative in (   ).
I actually like students to ALWAYS use (  ) when substituting in for ANY number…

Examples

solve:

x² when x = -3

(-3)² = 9

  -x² when x = -3

-(-3)² = -9

10- x² when x = -3

10 - (-3)² = 10 -9 = 1