Hello there!
324 + 36^2 = x^2
324 + 1296 = x^2
1620 = x^2
-x^2 + 1620 = 0
-x^2 = 0 - 1620
-x^2 = -1620
We don't want to leave the variable with a negative sign, so we should divide both sides by -1 to remove the negative sign
-x^2/-1 = -1620/-1
x^2 = 1620
Then take square root
x = +- √1620
x =18√5 or x = -18√5
I hope this helps!
