ex1.6_17

$u$ $\quad \sqrt{u} - 14=0$

We isolate the radical, and solve by squaring.

\sqrt{u}-14 = 0\\[0.25 in] \sqrt{u} = 14\\[0.25 in] (\sqrt{u})^2 = 14^2\\[0.25 in] u=196

It is important that you check your solution by substituting into the original equation:

\sqrt{196}-14 = 14-14=0.