A consumer electronics company is comparing the brightness of two different types of led screens for use in its television sets. Screen type a has mean brightness of 75 and standard deviation of 8, while screen type b has mean brightness of 70 and standard deviation of 12. A random sample size 36 is selected from screen type a where the sample size for screen type b is 25. Find the approximate probability that x¯ a − x¯ b exceeds 4?

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:

it has the same slope and a different y-intercept

hope this : )