Given that the m3 and m4 are both supplementary angles, we can therefore conclude that when we sum them up we get 180. Because supplemantary angles add up to 180.
Thus;
m3+m4=180
(3x-16)+(x+84)=180
opening the brackets we get:
3x-16+x+84=180
3x-x-16+84=180
2x+68=180
2x=180-64
2x=112
thus;
x=112/2
x=56
The answer is x=56
