#a: Sometimes true
Because it can be acute angles or obtuse angles.
b:Never true
Because if x and y are right angles then x and y equal to 90 degree but supplementary angles equals to 180 degree.
c:Always true
Because Both complementary and right angles equals to 90 degree
#6:Neither
7:complementary angles
8:complementary angles
9:Supplementary angles
10:Supplementary angles
11:Neither
Look at the attached picture ⤴
I have solved other questions there.
Hope it will help u....
