Given that :
M∠ABC=(6x+8)°
and
M∠DEF=(12x−8)°
it is given that the two angles are supplemetary
for supplementary angles
Sum of angles = 180
M∠ABC + M∠DEF = 180
inserting the values given
(6x+8)° + (12x−8)° = 180
(6x + 12x) + (8 - 8) = 180
18x = 180
x = 180/18
x = 10
inserting the values of "x" in each angle
so
M∠ABC=(6x+8)° = (6(10) + 8) = 68°
and
M∠DEF=(12x−8)° = (12(10) - 8) = 112°
