Question

John says the transformation rule (x, y) Right-arrow (x + 4, y + 7) can be used to describe the slide of the pre-image (4, 5) to the image (0, –2). What was his error?

Answer 1

Instead of moving right 4 times and up 7 times, John moved left 4 times and down 7 times.

Explanation:

(x + 4, y + 7) = Right 4, Up 7

NOT

(x - 4, y - 7) = Left 4, Down 7

Answer 2

The transformation rule should be applied to the pre-image. The application of the rule results in the point (8, 12). The transformation rule was applied to the wrong point.

Explanation:

Sample Response:The pre-image is the point you start with. To check the transformation rule, substitute the values of the coordinates (4, 5) into the rule. You get (4, 5) → (4+4, 5+7). Simplify to get (4, 5) → (8, 12). This is the image. Instead the rule was applied to the image. This is the source of the error.