###### Example3.3.4

Solve for $$x$$ in $$y=mx+b\text{.}$$ (This is a line's equation in slope-intercept form.)

In the equation $$y=mx+b\text{,}$$ we see that $$x$$ is multiplied by $$m$$ and then $$b$$ is added to that. Our first step will be to isolate $$mx\text{,}$$ which we'll do by subtracting $$b$$ from each side of the equation:

\begin{align*} y\amp=m\attention{x}+b\\ y\subtractright{b}\amp=m\attention{x}+b\subtractright{b}\\ y-b\amp=m\attention{x} \end{align*}

Now that we have $$mx$$ on it's own, we'll note that $$x$$ is multiplied by $$m\text{.}$$ To “undo” this, we'll need to divide each side of the equation by $$m\text{:}$$

\begin{align*} \divideunder{y-b}{m}\amp=\divideunder{m\attention{x}}{m}\\ \frac{y-b}{m}\amp=\attention{x}\\ x\amp=\frac{y-b}{m} \end{align*}
in-context