I think it should be -6, because line segment equals 12 and it's midpoint will be 12/2 = 6, so you must go down by 6 from (0,0) point on y axis which is 0-6=-6
So the point will be (0, -6)
Y should equal 8. Plug in the variable X. So (-9) times (-2) equals 18. Now the equation is 18-3y=6. 18 plus 6 equals 24. 3y = 24. 24 divided by 3 is 8.
Using the sum of interior angles equation;
(n-2)180=sum
(n-2)180=2340
n-2=2340/180
n-2=13.5
n=13.5+2
n=15.5
However, the problem is that a polygon cannot have "half" as side. Therefore, there might be a problem in the question or there is no solution to such a question.
Hope I helped :)
17/50 is 34% as a fraction!