Question 18
The number of different ordered pairs $(x,y)$ which satisfy the equation
$$2x^2-2xy+y^2=169$$
where x and y are integers and $x\ge0$ is
$$2x^2-2xy+y^2=169$$
where x and y are integers and $x\ge0$ is
Australian AMC 2013 - Senior Question 18
AMC AUSTRALIA · Australian AMC 2013 - Senior