21. write the equation of the line that is
perpendicular to y = -x - 11 and passes through
the point (9,2).

When a line is given in the form

The slope of the line is m. So, in this case, the slope of is -1.

Given a slope , you find the slope of a perpendicular line by imposing

So, if the given line has slope -1, a perpendicular line has slope given by

and thus

So, we want a line with slope 1 and passing through (9,2). Using the fomula

we get

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:

50

step-by-step explanation: