Answer:
[tex]\large\boxed{d=\dfrac{e^2+e}{1-3e}}[/tex]
Step-by-step explanation:
[tex]\dfrac{d-e}{3d+e}=e\\\\\dfrac{d-e}{3d+e}=\dfrac{e}{1}\qquad\text{cross multiply}\\\\(1)(d-e)=(e)(3d+e)\qquad\text{use the distributive property}\\\\d-e=3de+e^2\qquad\text{add}\ e\ \text{to both sides}\\\\d=3de+e+e^2\qquad\text{subtract}\ 3de\ \text{from both sides}\\\\d-3de=e^2+e\qquad\text{distribute}\\\\d(1-3e)=e^2+e\qquad\text{divide both sides by}\ (1-3e)\\\\d=\dfrac{e^2+e}{1-3e}[/tex]
