Find the measure of angle 8, 7, 6, 5

Question

measure of angle 7 is 2x+15
measure of angle 8 is 3x

The diagram is a X shape but the top and bottom is more squished down basically.

5 on the left
6 on the top
7 on the right
8 on the bottom

Please help I cant find the formula to do this.
Also please add the formula for finding the answer.
Thank you

Answer 1

o 6 o
o o
5 o 7
o o
o 8 o
The sum of the four angles equals 360°.
∠ 5= ∠ 7 (vertically opposite angles)
Similarly
∠ 6= ∠ 8 (vertically opposite angles)
Sum of the four angles
∠5+∠6+∠7+∠8=360°
2( 2x+15 + 3x) = 360°
solve for x and hence each of the four angles.