Answer:
Step-by-step explanation:
Two supplementary angles add up to 180°
Suppose x + y = 180 and y = x - 40
first we substitute y by x - 40 in the equation x + y = 180 ,we get:
x + (x - 40) = 180
then
2x - 40 = 180
then
2x = 180 + 40
= 220
then
x = 220/2
= 110
therefore
y = 110 - 40
= 70