Think about what happens to each point on the line $\displaystyle {y}={x}$ when you add or subtract a number from all $\displaystyle {y}$-values. The original line passes through the points $\displaystyle {\left({0},{0}\right)}$, $\displaystyle {\left({1},{1}\right)}$, and $\displaystyle {\left(-{1},-{1}\right)}$.