The population of Medford High School is 800 students and the population of Westville High School is 1240 students. The population of Medford High has been increasing at a rate of 30 students per year, while the
population of Westville High has been decreasing by 25 students per year. If these rates remain constant, in how
many years will the populations of the two schools be the same? How many students will that be?

given that triangle abc is transformed two times to get triangle

a"b"c"

first abc is transformed in to a'b'c' as follows:

the coordinates of a are (1,-1) and transformed into a'(-1,1)

similarly b (4,-2) became b'(-4,2) and

c(7,-2) became c'(-7,2)

i.e. (x,y) becomes (-x,-y)

this is nothing but reflection about a point here origin.

thus first transformation is reflection on the origin.

next is exactly shifting 3 units down

source: