In order to determine which ordered pair is a solution of the equation, we have to understand that if we replace the variables into values, the equality must remain. The first value of the ordered pair represents the "x" variable and the second value represents the "y" variable.
So, for every option:
a)
There is NOT equality
b)
There is NOT equality
c)
There is NOT equality
d)
There is equality
Finally, the only ordered pair that fulfill the equality is
The length of the first two sides of a triangle must be greater than the length of the last side. If the longest length were 18, the first two sides would be too short. 36-18=18, 18 is equal not greater than 18 which means the sum of the first two sides are too short.