Question

please answer this question

Answer 1

According to question,
n(n-3)/2=9

${n}^{2} - 3n = 18$
${n }^{2} - 3n - 18 = 0$
n2-6n+3n-18=0
n(n-6)+3(n-6)=0
(n-6)(n+3)=0
Hence,n=6 or -3
So the polygon has 6 sides (-3 is impossible) Please Make it brainliest.

Answer 2

it means n(n-3) / 2 =9
n^2-3n=18==>n^2-3n-18=0
then simplifying this n=6 ,,
so the polygon has 6 sides