A= 82 – 8°
b = 5x + 25°
solve for x and then find the measure of b:

x = 11

m∠B = 80°

Step-by-step explanation:

If two parallel lines are cut by a transversal, the corresponding angles are congruent

m∠A = m∠B

8x - 8 = 5x + 25 ... minus 5x and add 8 both side

8x - 5x = 25 + 8

3x = 33

x = 11

m∠B = 5 x 11 + 25 = 80°

check: m∠A = 8 x 11 -8 = 80

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50