McGraw Hill Glencoe Algebra 1, 2012
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McGraw Hill Glencoe Algebra 1, 2012 View details
3. Rational Exponents
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Exercise 86 Page 412

Practice makes perfect
a

We are given an equation that shows the number of possible random walks w.

w= d^nHere, n is the number of steps you take in a d-direction random walk. We are asked to find the number of steps taken in a 2-direction random walk if there are 4096 possible walks. To do so, we will substitute 2 for d, and 4096 for w in the equation.

w=d^n
4096= 2^n
2^(12) = 2^n

By the Power Property of Equality, the exponents are equal to each other. 2^()darkviolet12=2^n ⇔ 12= n Therefore, 12 steps have been taken in a 2-direction random walk if there are 4096 possible walks.

b

This time we need to substitute 4 for d, and 65 536 for w in the equation.

w=d^n
65 536= 4^n
4^8 =4^n

By the Power Property of Equality, the exponents are equal to each other. 4^()darkviolet8=2^n ⇔ 8= n Therefore, 8 steps have been taken in a 4-direction random walk if there are 65 536 possible walks.

c

For this part, we are asked to find the number of directions if a walk of 7 steps has 2187 possible walks. To find it, we will substitute 7 for n and 2187 for w in the equation.

w=d^n
2187= d^7
3^7 =d^7

In order for this equality to hold, the bases should be equal because of the Power Property of Equality. 3^7= d^7 ⇔ 3= d Therefore, 3 directions could be taken at each step.