Chapter 12 - Vectors and the Geometry of Space - 12.5 Equations of Lines and Planes - 12.5 Exercises - Page 871: 23

$x-2y+5z=0$

The general form of the equation of the plane is: $a(x-x_0)+b(y-y_0)+c(z-z_0)=0$ or, $ax+by+cz=ax_0+by_0+cz_0$ Plugging in the given values, we get $1x-2y+5z=1(0)-2(0)+5(0)$ After simplification, we get $x-2y+5z=0$