Question

Quadrilateral ABCD is a rectangle. If BDC = 7x + 1 and ADB=9x - 7, find BDC.

Answer 1

$\huge\boxed{45^\circ}$

See the attached diagram.

Together, angles BDC and ADB form a right angle, which is 90 degrees.

The angles are split straight down the middle, meaning they're equal to each other. This means each one is equal to half of 90 degrees, which is 45 degrees.