Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
1. Exponential Functions
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Exercise 52 Page 280

Find this year's and next year's sales. Then, use them to write a general equation.

About 4681

Practice makes perfect
We know that last year 3300 gas grills were purchased. The store expects grill sales to increase by 6 % each year. With these in mind, let's write the expression for this year's expected sales. 3300+ 3300 * 0.06 ⇔ 3300(1+ 0.06) Similarly, let's write the sales of the next few years, assuming 0 is the last year.
Years Previous Year's Sales Expected Sales Rewrite
0 - - 3300(1+0.06)^0
1 3300 3300(1+ 0.06) 3300(1+0.06)^1
2 3300(1+0.06) 3300(1+0.06)(1+ 0.06) 3300(1+0.06)^2
3 3300(1+0.06)^2 3300(1+0.06)^2(1+ 0.06) 3300(1+0.06)^3
We see that the exponent of the term (1+0.06) increases as the years increase. Hence, we can write the equation below. y=3300(1+0.06)^x Here, x represents the number of years and y represents the expected number of sales. To find the sales in Year 6, we will substitute 6 for x into the function y=3300(1+0.06)^x.
y=3300(1+0.06)^x
y=3300(1+0.06)^6
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Simplify right-hand side
y=3300(1.06)^6
y=3300(1.41851 ...)
y=4681.11307 ...
y=4681
In Year 6, the store expects to sell about 4681 grills.