Answer:
m∠ABD = 96
Explanation:
Given
m∠ABC = 5/2x + 18
m∠CBD = 4x
Required
Determine m∠ABD
From the given parameters, we understand that:
∠ABC ≅ ∠CBD
This implies that:

Collect Like Terms

Take LCM


Cross Multiply


Divide through by -3

m∠ABD can be calculated using:
m∠ABD = m∠ABC + m∠CBD

Substitute 12 for x



Hence;
m∠ABD = 96