Difference of supplementary angles is 70 degrees

Question

the difference between two supplementary angles is 70 degree. Find the measure of each angle. 

Answer 1

Let the angles be X and Y

Supplementary angles add up to 180 degrees

So X+Y = 180

and X - Y = 70

Adding two equations 

2 X = 250

X = 125 degrees

Y = 180 - 125 = 55 degrees