# How do you simplify (sqrt10 - 9) ^2?

##### 1 Answer

We are going to use the identity

${\left(A - B\right)}^{2} = {A}^{2} - 2 \cdot A \cdot B + {B}^{2}$

Hence we have that

(sqrt10-9)^2=(sqrt10)^2-2*sqrt10*9+9^2= 10-18*sqrt10+81=91-18*sqrt10