Answer:
q = 20
Explanation:
The two angles formed, angle 78 and angle (5q + 2), are adjacent and share the same vertex. Plus they both form to make a straight angle. Hence, we can conclude these angles are supplementary as they both combine to make a straight angle (which is equal to 180 degrees and is the definition of a supplementary angle).
Let's set up an equation saying that these two angles added together all equal to 180 degrees:
78 + (5q + 2) = 180
Solve for q by combining like terms first:
80 + 5q = 180
Get rid of constants to get q alone:
5q = 100
Finally get rid of coefficients:
q = 20