Friday,+February+5,+2010Set3

Worksheet:

1. Jenna 1/2= a x b^o 5=a x b^1 a=1/2 5=1/2b b=10 f(x)=1/2(10)^x

2. Maya 48 = a • b^2 --> 48/b^2 = a 3/4 = a • b^-1 --> 3/4 = 48/b^2 • 1/b --> 3/4 = 48/b^3 --> b^3(3/4 = 48/b^3) --> 3b^3/4 = 48 --> 4(3b^3/4 = 48) --> 3b^3 = 192 --> 1/3(3b^3 = 192) --> b^3 = 64 --> b=4 48/b^2 = a --> 48/16 = a --> a = 3
 * f(x) = 3 • 4^x**

3. Elena 18 = ab^(1/2) ---> 18/b^(1/2) = a ---> 18/√ b X √ b/√ b = 18b^(1/2)/b ---> a = 18b^(1/2)/b 2 = [18b^(1/2)/b]b^(-1/2) ---> 2 = [18b^(1/2)/b] X [1/b^(1/2)] ---> 2 = 18b^(1/2)/b^(3/2) ---> [2]b^(3/2) = [18b^(1/2)/b^(3/2)]b^(3/2) ---> 2b^(3/2) = 18b^(1/2) ---> divide both sides by 2 ---> b^(3/2) = 9b^(1/2) ---> divide both sides by b^(1/2) ---> b = 9 18[9^(1/2)]/9 = 6 ---> a = 6
 * f(x) = 6 (9)^x**

4. Jacob Answer?

5a. Tyler f(x) = 213649(1.08)^x

i. actually, i will be a senior in that year, but it will be $26912.49 ii. in the 2016-2017 school year it will be $36014.14 iii. $130372.34

5b. Sarah

i. f(3) = 51991(1.08)³ f(3) = $65,493.69

ii. f(6) = 51991(1.08)⁶ f(6) = $82,503.18

iii. Total Cost = f(3) + f(4) + f(5) + f(6) f(4) = 51991(1.08)⁴ f(4) = $70,733.18 f(5) = 51991(1.08)⁵ f(5) = $76,391.84 Total Cost = 65,493.69 + 70,733.18 + 76,391.84 + 82,503.18 Total Cost= $295,121.89

6a. Max 2^2x - 2^x - 6 = 0 Q=2^x Q^2 - Q - 6 = 0 (Q-3)(Q+2) = 0 Q=3 or -2

3=2^x log3=log2 x x x=log3/log2 x=1.585 I don't know why it's red. I don't know how to change the color either sorry!

6b. Josh 3^2x-5 * 3^x + 4=0 3^2x * 3^x=1 How is this? You need to look at this as a quadratic equation!! 3^3x=1 3x * log(3)=log(1) divide both sides by log(3) 3x=0 x=0

6c. Dan

6d. Drew 27x^3 - 28x^(3/2) + 1= 0 Q=x^3 27Q - 28Q^(1/2) + 1 = 0 (27Q+1)(1Q+1) = 0 Q=-1/27 or -1 -1/27^3 = -.00005 1^3 = 1 6e. Davis Answer?

6f. Erica 8^x+3 = (1/4)^3x-6 2^3x+9 = 2^-6x-12 3x+9 = -6x+12 9x = 3 x = 1/3

6g. Carly good work! 6h. James (x^2/3)^3/2=(726/68.1)^3/2 x=34.808

6i. Austin okay, but how did you get here??? Please show your work!! x=1/1.140 6j. Nico x=1.71 Answer?