Question

qual e a formula que relaciona d e n

Answer 1

d=n(n-3)/2

20=n.(n-3)/2

40=n²-3n

n²-3n-40=0

b²-4.a.c

-3²-4.1.-40

9+160=V169=13

x=-b+-delta/2.a

x=-(-3)+-13/2

x1=5

x2=8