"The function 'x' might be used before it is defined " error is coming. can anyone help?

function [P1,P2,P3]=assignment1(PD)
a=(x-8)/.04;
b=(x-10)/.08;
c=(x-6)/.16;
while (a<=500) && (a>=150) && (b<=400) && (b>=100) && (c<=200) && (c>=50) && ((a+b+c)==PD)
    for x=0:0.1:50
        P1=(x-8)/.04;
        P2=(x-10)/.08;
        P3=(x-6)/.16;
    end
end

Answer 1

[Walter Roberson]

You probably want a structure more like

counter = 0;
for x = ...
  a = ...
  b = ...
  c = ...
  if (a<=500) && (a>=150) && (b<=400) && (b>=100) && (c<=200) && (c>=50) && ((a+b+c)==PD)
      counter = counter + 1;
      P1(counter) =(x-8)/.04;
      P2(counter) =(x-10)/.08;
      P3(counter) =(x-6)/.16;
  end
end