The answer
a) the main rule for transformations Rx-axis is as following
original (x, y) --------------- the final coordinates become (x, -y)
so the answer is A' (2, -5), B' (4,-6) and C' (3,-1)
b) just put the figure of y= 3, and check the value after projection
it is A' (2, 1), B' (4,0) and C' (3,4)
c) T<-2,5>, the main rule is as following
T(a, b) ----- applying on (x, y) is (a+x, b+y) for the transformed points
in our case, A' (0,10), B' (2,11) and C' (1,6)
d) the same method as above for d. T<3,-6>, we found
A '(5,-1), B '(7,0) and C ' (6,-5)