Find x if magnitude of (X,10)=26??
OK, I'm guessing here that what you've written down has something to do with vectors, yes?
If so, then
We have a vector V = (V1, V2), such that
Magnitude of V is ||V||, and
||V|| = sqrt(V1^2 + V2^2)
||V|| = sqrt(X^2 + 10^2)
26 = sqrt(X^2 + 10^2)
676 = X^2 + 100
X^2 = 576
X = 24