To find the equation for determining the angle measures, we start by observing that angle ABC measures 90 degrees, which is the sum of angle ABD and angle DBC.
Given:
- Angle A B D = 4x degrees
- Angle D B C = (7x - 9) degrees
Since angle A B C forms a right angle (90 degrees), we can write the equation:
\[ AB + BD = ABC \]
That is, we can set it up as:
\[ (4x) + (7x - 9) = 90 \]
Thus, we need to express it in the form provided in your question:
\[ (4x)° + (7x - 9)° = 90° \]
So the equation can be presented as:
(4x)° + (7x - 9)° = 90°
In the format requested: (4x)° + (7x - 9)° = 90°.