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Experience:  BA (Hons) in Mathematics from Oxford University
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# For the period 1985-2001,the number y in millions of cell

### Resolved Question:

For the period 1985-2001,the number y in millions of cell phone service subscribers in the U.S. can be modeled by the function y=0.7x^2-4.3+5.5 where x is the number of years since 1985. In what year were there 16000000 cell phone users.

and:::::

In Geometry: Use the given area A of the rectanghle to find the value of x. Then give the dimensions of the rectangle. A=91m^2 side is (x=2)m and long side is (2x=3)m
Submitted: 5 years ago.
Category: Homework
Expert:  M Hasan replied 5 years ago.
Hi there!

For the second question, is it x - 2 and 2x - 3??
Customer: replied 5 years ago.

Let me retype: Use the given are A of the rectancle to fine the value of x. Then give the dimensions of the rectangle.

A=91m^2, Right side is (x+2)m, bottom is (2x+3)m

Expert:  M Hasan replied 5 years ago.
A)

When y = 16,

16 = 0.7x^2 - 4.3x + 5.5

x = 8.01, x = -1.87 (rejected)

So approximately 8 years since 1985.

B)

91 = (x + 2)(2x + 3)

Solving this yields:

x = 5 and x = -17/2 (rejected)

Therefore,

x = 5

Hope this helps. If so, please click 'Accept'. Thanks! :)

Customer: replied 5 years ago.

Expert:  M Hasan replied 5 years ago.
Yes, I have answered the first question under A and the second under B.
Customer: replied 5 years ago.

I guess I don't understand. The question is A=91m@ The right and left of the rectangle are (x+2)m and the top and bottom are (2x+3)m. I have to find the value of x and then give the dimensions of the rectangle.

Customer: replied 5 years ago.

I guess I don't understand. The question is A=91m@ The right and left of the rectangle are (x+2)m and the top and bottom are (2x+3)m. I have to find the value of x and then give the dimensions of the rectangle.

Sorry that is A=91m^2

Expert:  M Hasan replied 5 years ago.
I'll explain again and try to make it clearer:

91 = (x + 2)(2x + 3)

Solving this yields:

x = 5 and x = -17/2 (rejected)

Therefore,

x = 5

Since the value of x is 5, the dimension are 5 + 2 = 7m and 2(5) + 3 = 13m.

Hence the dimensions are 7m (right and left) and 13m (top and bottom).

Hope this helps. If so, please click 'Accept'. Thanks! :)
Customer: replied 5 years ago.

Thank you, XXXXX XXXXX thank you.

Expert:  M Hasan replied 5 years ago.