please simplify the square root of x-2-7=3 radical equation?

√(x - 2) - 7 = 3
√(x - 2) = 3 + 7
√(x - 2) = 10
x - 2 = 10^2
x - 2 = 100
x = 100 + 2
x = 102

Hope you mean:-
√(x - 2) - 7 = 3
√(x - 2) = 10
x - 2 = 100
x = 102

PS
It is a good idea to use brackets to avoid confusion.
Indeed brackets are a MUST.

sqrt(x-2)-7=3
sqrt(x-2)=10
square both sides
x-2 =100
x=102

sqrt(x - 2) - 7 = 3

sqrt(x - 2) = 10

x - 2 = 100

x = 102