Depends upon what you mean to do...if want each combination of the four variables, then you write a set of nested for loops...
y=x(j)^k + m - 2*n;
Of course, for n=1:1 is superfluous; one simply defines n outside the loops for a constant value; one presumes that's not the real case. That leaves one with 10*10*11*1 calculations of y; the allocation of a place to store the results isn't shown above.
ndgrid may be of interest...