Let's solve the system by eliminating x. We need the coefficients of x to be additive inverses, so they will add to zero eliminating x. The LCM of 9 and 6 is 18. Let's multiply both sides of the first by 2 and both sides of the second equation by -3.
18x + 16y = 6
-18x + 36y = 33
The coefficients of x are 18 and -18, which add to zero. Now we add these two equations.
52y = 39
y = 39/52
y = 3/4
Now we substitute y with 3/4 in the first equation and solve for x.
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.
