## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$$x=1+\sqrt{2},\:x=1-\sqrt{2}$$
Solving the equation, we find: $$x^2-2x-1=0 \\ x=\frac{-\left(-2\right)\pm \sqrt{\left(-2\right)^2-4\cdot \:1\left(-1\right)}}{2\cdot \:1} \\ x=1+\sqrt{2},\:x=1-\sqrt{2}$$