+0  
 
0
56
1
avatar

How many ordered pairs of integers (x,y) satisfy x + |y| = y + |x| if -10 <= x <= 10 and -10 <= y <= 10.

 Feb 11, 2020
 #1
avatar+109740 
+1

Look  at the graph here :  https://www.desmos.com/calculator/gd9gbzpdwn

 

The equation will  be true  for  10  lattice points  [points with integer coordinates ]  in the 3rd quadrant

 

And it  will  also  be  true  for   11^2  = 121  lattice points  on  the grid  

0  ≤ x  ≤ 10  and   0  ≤ y  ≤ 10   

 

 

So.....the total lattice points =  10  + 121  =   131

 

cool cool cool

 Feb 11, 2020

50 Online Users

avatar
avatar
avatar
avatar
avatar
avatar