Question

I need help with those questions, please

Which of the following scale factors will result in an enlargement?

A.
k < –1
B.
–1 < k < 0
C.
0 < k < 1
D.
k = 1


After a dilation with a center of (0, 0), a point was mapped as (4, –6) → (12, y). A student determined y to be –2. Evaluate the student's answer.

A.
The student is correct.
B.
The student incorrectly calculated the scale factor to be –2.
C.
The student incorrectly divided by the scale factor instead of multiplying by it.
D.
The student incorrectly added the scale factor instead of multiplying by it.

Answer 1

For the first one, it is A. It has to have an absolute value |k|>1, since then each side will be multiplied by a length greater than one.

For the second one, the x-value is multiplied by 3, which is the scale factor. The correct y-value would be -6 x 3 = -18. Since they got -2, they divided by the scale factor instead of multiplying -> C is correct.