my teacher wants me to use this formula: x^{2}+(a+b)x+ab

I don't understand.

Please use this formula with this expression: (\(\sqrt[2]{3}+2)(\sqrt[2]{3}+1)\)

The 2's indicating that it is the second root are assumed when not written.

\((\sqrt{3}+2)(\sqrt{3}+1)\)

x = √3

a = 1

b = 2

Substitute x, a, and b, into x^{2}+(a+b)x+ab .

\((\sqrt{3})^2+(1+2)(\sqrt3)+(1)(2)\)

Simplify.

\(3+3\sqrt3+2 \\ 5+3\sqrt3\)