Finding Ordered pair question

  • Thread starter spoc21
  • Start date
  • #1
87
0

Homework Statement


Please find all ordered pairs of integers (x,y) such that x2 + 2x + 18 = y2


Homework Equations


x2 + 2x + 18 = y2


The Attempt at a Solution



Im not sure on how to begin. I tried square-rooting the expression, to solve for y, turning it into y = [tex]\sqrt{x + 2x + 18}[/tex]. I would greatly appreciate any help to get me started on this problem.

Thanks!
 

Answers and Replies

  • #2
35,622
7,498

Homework Statement


Please find all ordered pairs of integers (x,y) such that x2 + 2x + 18 = y2


Homework Equations


x2 + 2x + 18 = y2


The Attempt at a Solution



Im not sure on how to begin. I tried square-rooting the expression, to solve for y, turning it into y = [tex]\sqrt{x + 2x + 18}[/tex]. I would greatly appreciate any help to get me started on this problem.

Thanks!
It might be helpful to complete the square. Then you would have the difference of two squares being equal to -17.
 
  • #3
87
0
Hey, thanks for the help.
So after this step, do we use trial and error to find the correct solution. I am getting one ordered pair, (9,9), and (-9,-7) after all the math(since x, and y can only be integers). I would really appreciate it if you could confirm this.
Thank you
 
  • #4
35,622
7,498
Those ordered pairs you got aren't solutions. When you completed the square, what did you get for your equation?
 

Related Threads on Finding Ordered pair question

  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
2
Views
1K
Replies
4
Views
5K
  • Last Post
Replies
7
Views
2K
Replies
6
Views
1K
Replies
6
Views
1K
  • Last Post
Replies
13
Views
5K
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
4
Views
1K
Top