Line AB contains point A (-4, 1) and point B (-1, 3). Find the coordinates of A' and B' after a dilation with a scale factor of 2 with a center point of dilation at the origin. (1 point)

A' (-8, 2) and B' (-2, 6)

A' (-8, 2) and B' (2,-6)

A' (-5, -2) and B' (-2, 6)

A' (8,-2) and B' (2,-6)

1 answer

To find the coordinates of points A and B after a dilation with a scale factor of 2 and center of dilation at the origin, we can use the following formula for dilation:

\[ (x', y') = (kx, ky) \]

where \((x, y)\) are the original coordinates, \(k\) is the scale factor, and \((x', y')\) are the coordinates after dilation.

Given:

  • Point A has coordinates \((-4, 1)\)
  • Point B has coordinates \((-1, 3)\)
  • Scale factor \(k = 2\)

Now we apply the formula:

  1. For point A: \[ A' = (2 \cdot -4, 2 \cdot 1) = (-8, 2) \]

  2. For point B: \[ B' = (2 \cdot -1, 2 \cdot 3) = (-2, 6) \]

After dilation, the coordinates are:

  • A' is \((-8, 2)\)
  • B' is \((-2, 6)\)

Thus, the dilated coordinates are:

  • A' (-8, 2) and B' (-2, 6)

The correct choice is: A' (-8, 2) and B' (-2, 6).