Finding the equation of a plain with a point and normal vector, Unsure how they got RHS of final equation

Question

The question is "Find the plain through point (-1, 1/2 , 3) and with normal vector i + 4j + k.

I have:

$$ \langle1, 4, 1\rangle *\langle x+1, y-1/2, z-3\rangle$$ $$(x+1)+(4y-1/2)+(z-3)$$ $$ x+4y+z= -(1+-1/2+-3)= 2.5$$

The answer is supposed to be 4 instead of 2.5, though the rest of the equation on the left side is correct.

Answer 1

$(x+1)+4(y-1/2)+z-3 = 0 \Leftrightarrow x +4y +z - 4 = 0.$