#### Answer

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

#### Work Step by Step

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}