Question 111663
Solve and check for extraneous roots.
{{{sqrt(y+9) = 1}}} Square both sides. This might introduce extraneous roots.
{{{y+9 = 1}}} or {{{y+9 = -1}}} Subtract 9 from both sides in both of these.
{{{y = -8}}} or {{{y = -10}}}
Check solutions:
{{{sqrt(y+9) = 1}}} Substitute y = -8.
{{{sqrt(-8+9) = 1}}}
{{{sqrt(1) = 1}}} Ok
{{{sqrt(y+9) = 1}}} Substitute y = -10
{{{sqrt(-10+9) = 1}}}
{{{sqrt(-1) = 1}}} Not valid! This is an extraneous root.