How to change variable value for every iteration in a for loop?

I have an equation within a for loop that uses multiple variables. All of the variables (except for variable a) are given in a txt file.

I want variable a to change in value after every loop in this for loop:

a = 5, 10, 15, 20, 25

length of x is 200

%Txt file data
f = data(:,1); %Length is 200
z = data(:,2); %Length is 200
x = data(:,3); %Length is 200

a = [5; 10; 15; 20; 25]

for n=1:length(x)
    l(n) = f(n).*(a)-((z(n)).*(a));
end

Mathematically, it would look like this:

l(n) = f(n)*(5) - (z(n)*(5)) <<For 200 iterations>>

then it would loop to the next a value:

l(n) = f(n)*(10) - (z(n)*(10)) <<For 200 iterations>>

then it would loop to the next a value:

l(n) = f(n)*(15) - (z(n)*(15)) <<For 200 iterations>>

Answer 1

[the cyclist]

for na = 1:length(a)
    for n=1:length(x)
        %Coefficient of Lift at each panel
        l(n) = f(n).*(a(na))-((z(n)).*(a(na)));
    end
end