First you have to get the variable by itself, by adding 50 to both sides:
Then you have to take the square root of both sides, remembering that a square root can be plus or minus:
x=sqrt of 50 or x = negative sqrt of 50
The square root of 50 can be factored/simplified, because 50 is the same as 2*25, and 25 is a perfect square. The square root of 25 part becomes 5, and the 2 remains in the square root.
So your 2 answers are:
Hope that helps!