Chapter 2 - Solving Equations - 2-5 Literal Equations and Formulas - Practice and Problem-Solving Exercises - Page 112: 21

$x=\frac{t}{r+s}$

We are trying to isolate the variable $x$ in the equation $\frac{rx+sx}{t}=1$ To do this, first we will multiply both sides by $t$: $t(\frac{rx+sx}{t}=1)$ $rx+sx=t$ Then, we will factor out the $x$ using the distributive property: $x(r+s)=t$ Then, we will divide by $r+s$ to isolate $x$: $x=\frac{t}{r+s}$