## College Algebra 7th Edition

$x=-1$ or $x=-21$
We solve by completing the square: $x^{2}+22x+21=0$ $x^{2}+22x=-21$ $x^{2}+22x+11^{2}=-21+11^{2}=-21+121=100$ $(x+11)^{2}=100$ $x+11=\pm\sqrt{100}=\pm 10$ $x=-11\pm 10$ $x=-11+10=-1$ or $x=-11-10=-21$ So we have: $x=-1$ or $x=-21$