When God sneezes, what do we say?​

Which of the following is not a subset of {1,2,3}?

How to simply and write the answer n a whole number

Right ∆abc has coordinates a(-7, 3), b( -7, 10), and c(-1, 3). the triangle is reflected over the x - axis and then reflected again over the y - axis to create ∆a'b'c'. which are the coordinates of vertex a'?