Question

using the completed-square form (x-4)^2-21 to solve the equation x^2-8x-5=0, leaving the answer in exact (surd) form

Answer 1

\[x^2-8x=5\]
\[(x-4)^2=5+4^2=21\]
\[x-4=\pm\sqrt{21}\]
\[x=4\pm\sqrt{21}\]

Answer 2

i love the word "surd" we don't use it much anymore

Answer 3

you can use quadratic formula also