Word problem.

Rainbow

New member
Joined
Apr 19, 2013
Messages
14
Find two consecutive odd numbers such that the sum of their squares is 130.

I found out that it was 9(squared) + 7(squared), but I have to represent this as an quadratic equation and be able to solve it for 7 and 9.
 
Find two consecutive odd numbers such that the sum of their squares is 130.

I found out that it was 9(squared) + 7(squared), but I have to represent this as an quadratic equation and be able to solve it for 7 and 9.

Two consecutive odd numbers can be represented as (2*n-1) & (2*n+1).

now continue....


Please share your work with us .

If you are stuck at the beginning tell us and we'll start with the definitions e.g. cost, equity & debt.

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217
 
Since the squares are added (not multiplied), isn't it much easier to use n and n+2 ?


Consider this alternative:


Let n - 1 = the smaller odd integer

Let n + 1 = the larger odd integer


\(\displaystyle (n - 1)^2 \ + \ (n + 1)^2 \ = \ 130\)



\(\displaystyle n^2 - 2n + 1 \ + \ n^2 + 2n + 1 \ = \ 130 \)



\(\displaystyle 2n^2 + 2 \ = \ 130\)



\(\displaystyle n^2 + 1 \ = \ 65\)



\(\displaystyle n^2 \ = \ 64\)



Continue . . .



Rainbow, 7 and 9 are not the only consecutive odd numbers such that the sum of their squares is 130.

-9 and -7 are also consecutive odd numbers with the same property.
 
Top