word problem with a radical

[glennda5]

7) Suppose that N?x+2 models the number of cases of an infection, in millions, of a disease x years from now.

a) How many cases of the infection will there be 16 years from now?
In this particular question I made an equation
N=?16+2, N=?18, N=3?2, N=4.24 is this right so it would be 4.24 million cases



b) In how many years will there be 7 million cases?

On this particular question I put 7=?x+2 is that correct what would go into x

 

[candace]

Glennda

I have ran into the same problem when I figure it out I will be happy to let you know

 

[burford99]

I have the same problem when I figure it out I will let you know

 

[mmm4444bot]

N = ?(x+2) models the number of cases of an infection, in millions, of a disease x years from now.

We need parentheses around this radicand to show everybody the correct order of operations!

How many cases of the infection will there be 16 years from now?

N = ?(16+2)

N = ?18

N = 3?2

N = 4.24

… it would be 4.24 million cases

This is correct, but I would write 4.2 million (unless you're told to provide two decimal places).

[In] how many years will there be 7 million cases?

On this particular question I put 7 = ?(x+2)

[Is] that correct[?]

[What] would go into x[?]

Nothing "goes into x". The value of x is what you're trying to find! (You already made the subsitution, when you wrote 7 for N.)

7 = ?(x + 2)

The first step to solve this equation for x is to square both sides.

After that, the remaining steps should be clear.

Always check your answer when you square both sides of an equation while solving because the act of squaring both sides of an equation can introduce false results.

 

[glennda5]

Thank you for your help, I got it now!