You can
put this solution on YOUR website!sqrt(t+12)-t=0
then
sqrt(t+12)=t
then
t+12=t^2
t^2-t-12=0
then
t= (1+7)/2 or t= (1-7)/2
then t=4 or t=-3 (potential solutions)
if t=4
sqrt(4+12)-4=sqrt(16)-4=0 (4 is a solution)
if t=-3
sqrt(-3+12)-(-3)=sqrt(9)+3=6 (-3 is not a solution)
Solution : t=4