640 x 0.30= 192
640-192= 448
448 is the answer
You have the right idea so far, but you forgot to finish it up.
Point slope form is
y - y1 = m(x - x1)
where m is the slope, and (x1,y1) is the point the line goes through. As you can see, we have infinitely many choices for (x1,y1). If you use the y intercept point (0,5), then
y - y1 = m(x - x1)
y - 5 = -1(x - 0) ..... this is one of infinitely many possible answers
OR
If you use the point (2,3), then we'd say
y - y1 = m(x - x1)
y - 3 = -1(x - 2) ..... which is another possible answer
There are infinitely many other choices, but I'm only picking the points in which your teacher has shown as big dots.
By the way, nice work on getting the correct answer for the slope-intercept form.
A'(-9,4)
B'(-4,4)
C'(0,-4)
D'(-5,-4)
20/6 because 20 x 3 = 6 x 10 = 60. 309 is equivalent to 10/3 because 30 x 3 = 9 x 10 = 90.
40/12 is equivalent to 10/3 because 40 x 3 = 12 x 10 = 120.
It is easy try to figure it.
If you did not figure it out the answer is
A. I think is 24 not sure.
B. I think it is 18 not sure.