Let's check the dot product .
v.w = 5(4)-2(10) = 20 -20 =0
So the dot product is not 20 . And since the dot product is zero, so they are perpendicular.
And the y component of w is 10.
So correct options are first and third .
The answer is
X=10 or X= -4
I'm more visual, but if you're not, and this confuses you, ask me, and I'll explain it.
