Answer
$x+4y+z=4$
Work Step by Step
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
$x+4y+z=1(-1)+4(1/2)+1(3)$
After simplification, we get
$x+4y+z=4$
