Belinda wants to invest $1000. The table below shows the value of her investment under two different options for three different years: Number of years 1 2 3
Option 1 (amount in dollars) 1100 1200 1300
Option 2 (amount in dollars) 1100 1210 1331

Part A: Option 1 is exponential because it does not increase by a constant rate. Option 2 is linear because it increases by a constant rate.

Part B:

For option 1: a(b)^x

a=1000 and b=1100/1000=1.1

the function will be:f(n)=1000(1.1)^x

For option 2:

Since the price increases by $100 each year, its linear.

Here would be the function: f(n)=1000+100(n)

Part C: Invest for 20 years in option 1: Yes.

f(20)=1000(1.1)^20

=1.1^20=6.72750

=6.72750x1000

=6727.50

y=6727.50, which is the price of the investment in 20 years.

For option 2:

f(20)=1000+100(20)

=1000+2000

=3000, which is the price the of the investment in 20 years.

If she uses option 2 rather than option 1, she will loose $3727.5

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.