A variable with a fraction exponent can be rewritten using a radical.
The equations would be A. radical equation
There is no triangle. Maybe the image messed up?
You will need too choose B
<BAC = <DEC = 30°
<BCA = <DCE = 70°
<CDE (or m<D) = 180° - <DEC - <DCE
<CDE = 180° - 30° - 70°
<CDE = 80°
The number that belongs in the green box is 80