Question

resolva a equação Cx,2=15​

Answer 1

Cx,2=15

x.(x-1)/2 = 15

x.(x-1) = 30

x² -x -30 = 0

∆=b² -4ac= 1 +120 = 121 ==> √∆=11

x= -b+√∆/2a = 1+11/2= 12/2= 6 ✓