If α and β are the zeroes of $x^2-8x+11$, the value of (1 + α)(1 + β) is:

Expand before substituting: $(1+\alpha )(1+\beta )=1+(\alpha +\beta )+\alpha \beta$. With $\alpha +\beta =8$ and $\alpha \beta =11$ this is $1+8+11=20$ — the zeroes themselves are irrational, so there is no need to find them. 19 forgets the leading 1; 4 computes $1-8+11$, flipping the sign of the sum; 88 just multiplies 8 by 11.