how to import data into matlab code when using fzero function.

I'm using fzero function to solve a complicated equation numerically. the equation depends on the intensity which is variable, so I have to call the intensity from another file to matlab program, then matlab program have to calculate the same equation for different values of intensity, so I will have in total the same equation repeated 20 times but each time with different value of intensity, and then I want to solve these equation one by one using fzero function. for this thing I don't know what code I should use to call the intensity values one by one to Matlab code, and I don't know how I should set the for loop for fzero function to call the final equations (which is 20) and solve them one by one and show the answer for each one.