Answer:
[tex]8x+13y = 130[/tex]
Step-by-step explanation:
sum of interior angles in a triangle is 180 degree
interior angles are (5x+3y)∘,(3x+20)∘, and (10y+30)
add all the angles and make it equal to 180
[tex]5x+3y+3x+20+10y+30= 180[/tex]
combine like terms
[tex]5x+3y+3x+20+10y+30= 180[/tex]
[tex]8x+13y+x+50= 180[/tex]
subtract 50 from both sides
[tex]8x+13y = 130[/tex]