Solve For n

[nycmathguy]

 

[MathLover1]

sqrt(n^2-12^2)=3^2...........square both sides

(sqrt(n^2-12^2))^2=(3^2)^2
n^2-144=(9)^2
n^2=81+144
n^2=225
n=sqrt(225)
n=15

check:

sqrt(15^2-12^2)=3^2
sqrt(225-144)=3^2
sqrt(81)=3^2
9=3^2
3^2=3^2

 

[nycmathguy]

sqrt(n^2-12^2)=3^2...........square both sides

(sqrt(n^2-12^2))^2=(3^2)^2
n^2-144=(9)^2
n^2=81+144
n^2=225
n=sqrt(225)
n=15

check:

sqrt(15^2-12^2)=3^2
sqrt(225-144)=3^2
sqrt(81)=3^2
9=3^2
3^2=3^2

We solve it like any other radical equation.