What is the first step in writing f(x)=6x^2+5-42 in vertex form

For a parabola  ax² + bx + c the vertex's  x equals -b/2a

a = 6 , b = 0

x = -0 / 2*6  => 0

Plug in x = 0  to find  the  y value :

y = 6 * 0² + 5 - 42 => - 37

Therefore the parabola  vertex is :

( 0 , - 37 )

if a < 0 , then the vertex  is a maximum value
if a > 0, then the vertex is a minimum value

minimum ( 0, -37 )

hope this helps!

The answer is the first one