I hope this helps you
5x^2+30x+65=0
5 (x^2+6x+13)=0
x^2+6x+13=0
a=1 b=6 c=13
disctirminant=b^-4ac
disctirminant=6^2-4.1.13
disctirminant=36-52
disctirminant= -16
x1= -6+square root of -16/2.1
x1= -6+4i/2=2i-3
x2= -6- square root of -16/2.1
x2= -6-4i/2= -3-2i
