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Lesson 3- using rules of exponents The exponent, tells the number of times that the base is used as a factor 2 3 is defined as 2 times 2 times 2
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Definition of negative exponents X -n = 1/x n 2 -3 = 1/2 3
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simplfy 1/3 -2 3 -3 -3 -2 3 -3 1/5 -2 5 -2 -5 -2 (-5) -2 -(-5) -2
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Product rule for exponents x m x n = x m+n
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Power rule for exponents (x m ) n = x mn
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Scientific notation Multiplying by a positive power of 10, moves the decimal point to the right. Multiplying by a negative power of 10, moves the decimal point to the left
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Simplifying expressions in scientific notation (4.2 x 10- 7 )(.0028) 2400(1.6 x 10 -10 ) (.0003 x 10 -6 )(4000) (.006 x 10 15 )(2000 x 10 4 )
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Lesson 6 finding percent of change Any fraction or decimal can be written as a percent. To write a decimal as a percent, multiply by 100(move decimal point 2 places to the left) To write a fraction as a percent, divide the numerator by the denominator, then multiply by 100
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examples Change.12 to a percent Change 8 to a percent Change 4/5 to a percent Change 22/8 to a percent Change.035 to a percent
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Percent of change Percent of change is the increase or decrease given as a percent of the original amount When the new amount is greater than the original amount, the change is a percent increase When the new amount is less then the original amount, the change is a percent decrease
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Percent of change Percent of change= amount of increase or decrease original amount
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practice Calculate the percent of change and tell whether it is an increase or decrease. From 120 to 168 From 6 to 5.1 From 18 to 72 From 240 to 60
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Determining new amount What is the new amount when 58 is decreased by 70%? 1. find amount of decrease 70% of 58=.70x58 = 40.6 2. subtract amount of decrease from original amount 58-40.6= 17.4 OR 1. subtract 70% from 100% = 30% 2. find 30% of 58 = 17.4
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What is the new amount when 125 is decreased by 15% 1..15 x 125=18.75 2. 125-18.75= 106.25 Or 1. 100%- 15%= 85% 2. 85% x 125 = 106.25
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Find new amount when 620 is increased by 350%. 1. find 350% of 620 = 3.5 x 620 =2170 2.add 2170 to 620= 2790 Or 1. add 100% to 350%= 450% 2. find 450% of 620= 4.5 x 620= 2790
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discount When an item in a store is on sale, the new price reflects a discount. The amount of discount is the difference between the old and new price and the percent of discount is a percent of discount
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When the price of an item increases, the increase is a markup, and the percent of change is a percent increase. A markup can refer to an increase in the retail price of an item or it can refer to the amount by which the wholesale cost of the item is increased. Marked up price=original price +markup =(wholesale price) + markup Sale price = original price - discount
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Find sale price A digital camera costs $128. It is being offered at a 25% discount. Find the sale price. Sale price = original price - discount S = 128 - 25% x 128 S = 128 -32= $96 Or 100% -25% = 755 75% of 128 = 96
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Finding marked up price A grocer buys watermelon from a farmer for $1.34 each and sells them at a 250% markup. What is the cost of the watermelon at the grocer's store. Marked up price= wholesale price+ markup = 1.34+ 250% of 1.34 =1.34 + 3.35 = 4.69
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Check for understanding Explain how to find the new amount when a number is increased by a percent. Explain the difference between a discount and a markup. A student states that a negative exponent means the exponential must be in the denominator. Is this correct? Explain.
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