Answer:
146°
Step-by-step explanation:
By the property of intersecting tangent and secant outside of a circle.
[tex](5x )\degree = \frac{1}{2} [(25x + 21) \degree - 96 \degree] \\ \\ (5x )\degree \times 2= (25x + 21 - 96) \degree \\ \\ (10x )\degree = (25x + 21 - 96) \degree \\ \\ 10x = 25x - 75 \\ \\ 75 = 25x - 10x \\ \\ 75 = 15x \\ \\ x = \frac{75}{15} \\ \\ x = 5 \\ \\ m (\widehat{DB}) = (25x + 21) \degree \\ \\ m(\widehat{DB} )= (25 \times 5 + 21) \degree \\ \\ m(\widehat{DB} )= (125 + 21) \degree \\ \\ \huge \purple{ \boxed{m( \widehat{DB} )= 146 \degree}} \\ \\ [/tex]
