Answer:
x = 20
∠B =150°
Step-by-step explanation:
Angles A and B are alternate interior angles formed by the intersection of a line with two parallel lines. Therefore, the measure of A and B is the same.
![∠A=∠B](https://img.qammunity.org/2023/formulas/mathematics/college/wgi4xkopme1otkhup7pprvv7yxx5jx612h.png)
Now since ∠A = 8x - 10 and ∠B = 3x + 90, the above equality gives
![8x-10=3x+90](https://img.qammunity.org/2023/formulas/mathematics/high-school/rqiwog1ho5gfr1xxrxltisjd359are0azr.png)
We just need to solve for x.
Adding 10 to both sides of the equation gives
![8x-10+10=3x+90+10](https://img.qammunity.org/2023/formulas/mathematics/college/spakcidfn3oedpicntmwa97o6pm1b5qsxm.png)