+16 Think of it this way, (2x+5y)+(3x+5)=180
Because the top line and the bottom line are parralel the two angles created by the line in between the parralel lines are supplementary and so they must also add up to 180.
Now use substitution.
because x=3y-5
2x+3y+2x+5y=180
substitute
12y-20+8y=180
20y=200
y=10
now substitute
2x+30+2x+50=180
4x=100
x=25
y=10 x=25
>=)
