Question

the coordinate of J' after a reflection of the triangle is about the line y= -x. The coordinates of J is (-2,-1)​

Answer 1

The reflection line is located at y = -x

For point J, x is -2, so y = -(-2), which equals 2.

When it is a reflection across Y, the X values remain the same.

Find the distance of the Y point to the reflection line,

The distance from -1 to 2 is 3 units.

The new point needs to be the same distance from the reflection line.

2 +  3 units = 5.

Point J' would be (-2,5)