Given that ∠XQR = 180° and ∠LQM = 180°, which equation could be used to solve problems involving the relationships between ∠XQM and ∠RQM?

Responses
A 180 + (140 − 7a) = (70 − 3a)180 + (140 − 7a) = (70 − 3a)
B 180 + (70 − 3a) = (140 − 7a)180 + (70 − 3a) = (140 − 7a)
C 180 − (140 − 7a) = (70 − 3a)180 − (140 − 7a) = (70 − 3a)
D (140 − 7a) − (70 − 3a) = 180(140 − 7a) − (70 − 3a) = 180
E 360 − (140 − 7a) = (70 − 3a)

The correct equation that could be used to solve problems involving the relationships between ∠XQM and ∠RQM is option A:

180 + (140 - 7a) = (70 - 3a)

how did you get this?