1. **State the problem:** We need to make $x$ the subject of the formula given by $$y = 1 - 9x$$. 2. **Write down the formula:** $$y = 1 - 9x$$. 3. **Isolate the term with $x$:** Subtract 1 from both sides: $$y - 1 = -9x$$ 4. **Divide both sides by $-9$ to solve for $x$:** $$x = \frac{y - 1}{-9}$$ 5. **Simplify the fraction by canceling the negative sign:** $$x = \frac{\cancel{y - 1}}{\cancel{-9}} = -\frac{y - 1}{9}$$ 6. **Final expression for $x$:** $$x = -\frac{y - 1}{9}$$ This means $x$ is expressed in terms of $y$ as $x = -\frac{y - 1}{9}$.