Question

find the equation of the images of the following lines when the reflection line is the x-axis

Answer 1

When the equation is reflected about the x-axis,

(x, y) → (x, - y)

The original equation is y = - x + 7

Therefore,

$\begin{gathered} f(x)=-f(x) \\ replace\text{ y with -y} \\ -y=-x+7 \\ y=x-7 \end{gathered}$