Answer:
B
Explanation:
x-5+3x-5+90=180 you set it up this way because you need to find what x is equal to and by adding those two equations plus 90 then setting the against 180 you can find x because all three angles in a triagnle add up to 180.
x-5+3x-5+90=180
4x-10+90=180 you combined like numbers
4x+80=180 combined like numbers
-80 -80 subtract 80 from both sides because you are trying to--- get x alone
4x=100 now to get x alone you have to divide 4 from both ---- sides
/4 /4
x=25 answer