How do i learn how to do this math ? I don’t know how to do it

Both angles measure 135 degrees.

Step-by-step explanation:

There is an image below showing my work. Sorry about the crinkled paper. You set both equations equal to each other and solve for x. You can then substitute x in for what you got. This will work for either equation. Since the equations are equal you only have to substitute it in for one equation but can do both.

the answer is 510

step-by-step explanation:

15 • 13 = 195

15 • 12 = 180

15 • 5 = 75

12 • 5 = 60

195 + 180 = 375

375 + 75 = 450

450 + 60 = 510