Chapter 1 - Section 1.2 - Formulas and Percent - 1.2 Exercises - Page 61: 20

a) $x=\dfrac{y-b}{m}$ b) $m=\dfrac{y-b}{x}$

a) Using the properties of equality, in terms of $ x ,$ the given formula, $ y=mx+b ,$ is equivalent to \begin{array}{l}\require{cancel} y-b=mx \\\\ \dfrac{y-b}{m}=x \\\\ x=\dfrac{y-b}{m} .\end{array} b) Using the properties of equality, in terms of $ m ,$ the given formula, $ y=mx+b ,$ is equivalent to \begin{array}{l}\require{cancel} y-b=mx \\\\ \dfrac{y-b}{x}=m \\\\ m=\dfrac{y-b}{x} .\end{array}