How many real roots does the function f(x)=x^2+8x-2

First find the determinant, Δ = b^2 - 4ac 
a = 1, b = 8 , c = -2 
Δ = 8^2 - 4*1*-2 
Δ = 64 + 8 
Δ = 72 > 0 
therefore there are two real roots!

Using the discriminant
for
f(x)=ax²+bx+c

the discriminant is b²-4ac
when it is
1. less than 0, there are no real roots
2. equal to 0, then there is 1 real root
3. more than 0, 2 real roots

given
f(x)=1x²+8x-2
a=1
b=8
c=-2
discriminat
8²-4(1)(-2)
64+8
this is greater than 0
2 real roots