Question

the number N, in millions, of hearing impaired individuals of age x can be approximated by N=-0.00006x^3+0.006x^2-0.1x+1.5. Approximate to the nearest million the number of hearing impaired individuals of age 25 and 45

Answer 1

Have you tried to calculate the answers?

Answer 2

no looking at my notes it is a scientific notation but thats all I know

Answer 3

Can you try calculating the first term (-0.00006x^3) by sustituting 25 for x?

Answer 4

0.9375

Answer 5

or 0.938

Answer 6

\[-0.00006x ^{3}=-(6\times 10^{-5})\times x ^{3}\]
\[-(6\times 10^{-5})\times 25^{3}=-0.9375\]

Answer 7

Ok I got a final answer of 3.69 .....would the nearest million be 4?

Answer 8

wait the first number is neg so Im wrong

Answer 9

The second term can be written as:
\[6\times10^{-3}\times x ^{3}\]
Can you substitute 25 for x and calculate?

Answer 10

3.75

Answer 11

Good work. So the calculation for age 25 years is:
-0.9375 + 3.75 -2.5 + 1.5

Answer 12

1.8125

Answer 13

would I round it to 2 million?

Answer 14

or 1.81

Answer 15

Gr8! Yes, you are required to round to 2 million. Do you want to try for age 45 and post back the answer for me to check?

Answer 16

awesome THANK YOU!!!! Sure give me a couple mins

Answer 17

15 million?

Answer 18

Check against my result for each term as follows:
-5.4675 + 12.15 - 4.5 + 1.5

Answer 19

yes that what I got answer 14.6175

Answer 20

Did you get all the signs right? I get 3.6825 million which rounds to 4 million.

Answer 21

I recalculated and got the same, I supose I hit the wrong sign somewhere

Answer 22

same as in 3.6825

Answer 23

Wonderful. Thanks for perservering :)

Answer 24

Auh THANK YOU for walking me through it!! Your a life saver :). This is my last class to get my associates degree and I am HORRIBLE with math

Answer 25

Good luck with your studies. I had to work very hard to get my math grades up so I know how you feel

Answer 26

thanks