Solve for y given the equation y = sqrt( x - x) and x=45.

We are given the equation $y = \sqrt{\sin x - \cos x}$ and $x=45$. We assume $x$ is in degrees.
Substitute $x=45^\circ$:

We know that $\sin(45^\circ) = \frac{\sqrt{2}}{2}$ and $\cos(45^\circ) = \frac{\sqrt{2}}{2}$.

The calculated value of $y$ for $x=45^\circ$ is 0. The problem states "given that $x=45, y=90$", which is inconsistent with our calculation. Based on the equation and $x=45^\circ$, the value of $y$ is: