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Solutions to the exercises

Exercise 1
a

f ( x ) = -100 ( x + 10 ) -3 + 40

b

x = -10 and y = 40 .

c

D f = , -10 -10 , and B f = , 40 40 ,

d

100 ( x + 10 ) 3 = 40 gives you ( x + 10 ) 3 = 2 1 2 and therefore x = -10 + 2 1 2 3 .
The x-intersect is ( -10 + 2 1 2 3 , 0 ) .

e

Determine the intersects with the graphing calculator and reading off the solution to the inequality: -8,73 x < 40,00 .

Exercise 2
a

16 = 1 2 x 5 gives you x 5 = 32 and x = 2 .
Solution for the inequality: x < 0 0 < x 2 .

b

2 x x - 10 = 80 gives you 2 x = 80 x - 800 and therefore x = 400 39 .
Solution for the inequality: x < 10 x > 400 39 .

Exercise 3
a

g ( x ) = 20 x 2 1 2 - 100

b

D f = [ 0 , and B f = [ -100 , .

c

x 2 1 2 = 5 gives you x = 5 2 5 , so ( 5 2 5 , 0 ) .

d

Graphing calculator: x 1,92

Exercise 4
a

16 x 1 4 = 1 2 x gives you x 3 4 = 32 and x = 32 4 3 .
Solution for the inequality: x 32 4 3 .

b

( 2 x - 40 ) 1 2 = 40 gives you 2 x - 40 = 1600 and x = 820 .
Solution for the inequality: 20 x < 820 .

Exercise 5
a

f ( x ) = 10 x -1 1 2 + 100 and g ( x ) = 10 x 1 2

b

Only the graph of f has asymptotes: x = 0 and y = 100 .

c

Graphing calculator: 0 < x < 100,02

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