What is an equation of the line that passes through the point (2, 4 and is perpendicular to the line whose equation is 3y = 6x 3?

Perpendicular line always have slopes that are negative reciprocals of one another.  Mathematically,

m1*m2=-1

So to be perpendicular to the line given, let's rearrange it to the point slope form of a line...

3y=6x ?3 (not sure what you wanted to type there)

anyway isolating y by dividing both side by three will leave 2x where 2 is the slope.

So for the other line to be perpendicular, m*2=-1, m=-1/2, now we have:

y=-x/2 +b, we can now you the point given to solve for b

4=-2/2 +b

4=-1+b

b=5 so

y=-x/2 +5 or more neatly

y=(10-x)/2