How to use find() to find unique values in equations?

Assume I have the following surfaces:

z1 = x + y and z2 = 2x + y

How can I use the find() function to find unique values of z for each equation given the same x and y values. By unique I mean values of z1 or z2 that are unique to each respective equation. For example, x and y = 0 would both give the same value for z1 and z2. That's what not what I care about. What I care about is knowing x and y values where z1 and z2 are both different.

I'm new to this so I might need a bit of a step-by-step explanation.

Thank you

Answer 1

[Azzi Abdelmalek]

Example

x=10; 
y=20
z1 = x + y
z2 = 2x + y
idx=z1==z2  % if idx is equal to 0, that means z1 and z2 are different

[A]

Thanks!

But how can find out the values of x and y where z is different?

[Azzi Abdelmalek]

What are the values of x and y?

[A]

Assume they have a range from -10 to 10.

Thank you

[Azzi Abdelmalek]

From your equations, z1 and a2 are equals if x+y is equal to 2*x+y, which means 2x=x, no matter what y is.

you don't need Matlab to resolve this, the solutions are (0,y), y belong to [-10,10]