zeroes are where the function equals 0 so
solve
0=x²-13x+67
factor
what 2 numbres multiply to get 67 and add to get -13?
nothing
so we use quadratic formula
for
0=ax²+bx+c

given
0=1x²-13+67
a=1
b=-13
c=67
note: √-1=i






there are actually no real zeroes of the function