Answer:
so u multiply negative four times nagative 1.5
Angle 1 is a vertical angle in relation to the given angle, 117°, so it has the same measure.
Angle 2 is a corresponding angle to angle 1 where the transversal crosses parallel lines, so it has the same measure. (It is also an alternate exterior angle with respect to 117°, so has the same measure.)
∠1 = ∠2 = 117°
53 + 4b=21--> 4b = -32--> b=-8