All points along which axis have $x$x-coordinates equal to $0$0?
$y$y-axis
$x$x-axis
If point $P$P has an $x$x-coordinate of $0$0, which axis must it lie on?
Consider the points $A$A and $B$B.
On the coordinate plane below, draw a triangle with vertices at $\left(0,0\right)$(0,0), $\left(5,0\right)$(5,0), and $\left(5,-7\right)$(5,−7).