Question

$P^{\prime }$ is the image of $P$ under reflection in the $x$-axis.
If the co-ordinates of $P^{\prime }$ are $(2,10)$, write the co-ordinates of $P$.

Answer 1

Given: $P^{\prime }$ is the image of $P$ reflected in the $x$-axis.

Coordinates of $P^{\prime }=(2,10)$

Let co-ordinates of $P$ are $(x,y)$.

Reflection in the $x$-axis, $M_x(x,y)=(x,-y)$

$\therefore M_x(x,y)=(2,10)$

So,

$x=2$

$-y=10\Rightarrow y=-10$

Hence, the co-ordinates of $P$ are $(2,-10)$.