Hi, thank you for posting your question here at Brainly.
All you have to do is add all the angles and equate to the total sum of angles for a quadrilateral.
360 = Angle Q + Angle P + Angle R + Angle S
Other relationships/equations are:
Q = 2P
R = 3b-19
S = 3b+10
Then, substituting...
360 = 2P + P + 3b - 19 + 3b + 10
360 = 3P +6b - 9
360 - 3P + 9 = 6b
6b = 369 - 3P
b = (369 - 3P)/6
b = 61.5 - 0.5P
Once you know the value of P, then you can determine the exact value of b.
