Matematika feladatok
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#457
n-szög szögösszege = 180*(n-2)
n >= 3
180*(n-2) = 100*n + 10*n*(n-1)/2
180*n - 360 = 100*n + 5*n^2 - 5*n
180*n - 360 = 95*n + 5*n^2
0 = 5*n^2 - 85*n + 360
n1,2 = (85 +- sqrt(85^2 - 4*5*360))/(2*5)
n1,2 = (85 +- 5)/10
n1 = 90/10 = 9
n2 = 80/10 = 8