Answer:
x=12
Explanation:
since they are supplementary they will have a sum of 180 degrees
The equation should look like this- (5x+4)+(4x+80)=180
after solving the equation- you get x=12
in order to see if that is correct you would plug in 12 where x is in our equation (5x+4)+(4x+80). which does equal 180 when 12 is plugged in
Therefore, 12 is your answer