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Monday, September 24, 2012

Algebra Honors (Period 5 & 6)


Exponents 4-1
In the expression 54 the number 4 is called the exponent and the number 5 is called the base
We call 54 the exponential form of 5⋅5⋅5⋅5 (which is the expanded form)
The exponent tells you the number of times the base is used as a factor.
bn = b⋅b⋅b⋅b⋅b⋅⋅⋅⋅b ( a total of n factors)
The expression bn tells you that b is used as a factor n times.

-2⋅p⋅q⋅3⋅p⋅q⋅p written in exponential form is -6p3q2

Be careful when an expression contains both parentheses and exponents
(2y)3 = (2y)(2y)(2y) = 8y3
and
2y3 means 2⋅y⋅y⋅y = 2y3
-34 = -81
(-3)4 = (-3)(-3)(-3)(-3) = +81
(1 + 5)2 = 36
1 + 52= 26
Simplify
(x –y)3/2x + y
for x = 2 and y = 5

-3

Simplify
x4 – a4
for x = 2 and a = 3
-65

[23 + 33] ÷ [23 + (-1)2] = (8 + 27) /9 = 35/9


Evaluating terms - this is what we have been doing all year... plug it in, plug it in!!
Remember to ALWAYS put the number you substitute in parentheses!!

2x2y + 5xy - 4, where x = -4 and y = 5
Substitute carefully:

2(-4)2(5) + 5(-4)(5) - 4
= 2(16)(5) +(-20)(5) - 4
= 160 +(-100) -4
= 160 -104
= 56

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