A straight line is also called a supplementary angle which equals 180 degrees. Angle DBC is a supplementary angle and angles ADB and ABC equals 180 degrees.
Your starting equation would be : 2x + 5x + 5 = 180
From here, combine like terms : 7x + 5 = 180
Subtract 5 from both sides : 7x = 175
Divide 7 on both sides : x = 25
From here, you need to insert the value of x (which is 25) into the equation for angle ABC (which is 5x + 5)
5(25) + 5
Angle ABC = 130 degrees
To ensure you have the correct answer, you can also find angle ADB (50) and add both values. If they add up to 180, you know for sure that you have the correct answer.
50 + 130 = 180 The answer is correct!
Just to be clear, angle ABC = 130 degrees
