Question

3.3 classwork - reflections - graded
state the image of the point (-2, -1) after a reflection across the line y = 1.

Explanation:

Step1: Analyze the y - coordinate change

The formula for reflecting a point $(x,y)$ across the horizontal line $y = k$ is $(x,2k - y)$. Here $x=-2$, $y = - 1$ and $k = 1$.

Step2: Calculate the new y - coordinate

Substitute the values into the formula: $2k - y=2\times1-(-1)=2 + 1=3$. The x - coordinate remains the same.

Answer:

$(-2,3)$