Question

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

Answer 1

We are going to use the identity

`(A-B)^2=A^2-2*A*B+B^2`

Hence we have that

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