Answer:
[tex]J = \dfrac{R}{5KRC - K}}[/tex]
Step-by-step explanation:
[tex]\begin{array}{rcll}\dfrac{1}{R} + \dfrac{1}{JK} & = & 5C &\\\\JK + R & = & 5JKRC & \text{Multiplied every term by JKR}\\JK & = & 5JKRC - R & \text{Subtracted R from each side}\\JK - 5JKRC & = & -R & \text{Subtracted 5JKRC from each side}\\J(K - 5KRC) & = & -R & \text{Removed the common factor J}\\J & = & -\dfrac{R}{K - 5KRC} & \text{Divided each side by (K - 5KRC)}\\\\J & = & \mathbf{\dfrac{R}{5KRC - K}} & \text{Distributed the -1}\\\end{array}[/tex]
