R - find a specific value in the matrix

Question

I’m having trouble finding a specific value in a matrix. The problem is that my matrix is too big to put here [360,181], so I’ll have to solve with an example.

x<- matrix(1:50, ncol=5)

I need something like:

x[x==14]

And he returns me:

[4,2]

Where respectively my value 14 is found in my row 4 and column 2.

Thank you!