Answer:
I believe it is the 3rd one down
Step-by-step explanation:
Because the two angles make an angle of 180, supplementary angles make one angle of 180 and it says that 2 and 3 are alike because they make a supplementary angle and there is a line dividing them that looks like both angles = 90 degrees
d = 1, so 1 - 10 - 2*1 + 7 = 8 + 1 - 10 - 3*1 is true!