Simplifying
2ab + 4ab = 0
Combine like terms: 2ab + 4ab = 6ab
6ab = 0
Solving
6ab = 0
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Divide each side by '6'.
ab = 0
Simplifying
ab = 0
I wrote my answer in the picture
<h2>
Answer:</h2>

<h2>
Step-by-step explanation:</h2>
In this problem we have two vectors:

So we need to find two things:

and:

FIRST:
In this case we have the multiplication of vectors by scalars. A scalar is a simple number, so:

SECOND:
If we name:

Then,
is the magnitude of the vector
. Therefore:

1.false
2. true
3.true
4.false
Hope this helps!