Answer:
x = 9
∠B = 40°
Step-by-step explanation:
because the lines are parallel, a and b are alternate angles. this means that they are equal. thus, we know that:
5x - 5 = 3x + 13
(add 5 to each side) 5x = 3x + 18
thus, 2x = 18 and x = 9.
we can now find ∠B by substituting 9 for x into the equation:
3x + 13
= 3 × 9 + 13
= 27 + 13
= 40°
i hope this helps! :D