Question

Find the coordinates of the reflection of (-4,1) across y=x

Answer 1

y = x, is slope 1, inclination 45°

Find distance from (-4,1) to y= x, -4= -4

Distance D= 4 - 1 = 3 units

Then coordinates of reflection are

3 units to right , from (-4,-4)

are (-4 + 3, -4)

Answer is

Reflection (-1, -4)