Last problem I need help with! Please click attached

Question

anonymous · Answer

attachment

anonymous · Answer

° = implies the two are perpendicular

anonymous · Answer

=0

anonymous · Answer

Let a= - xi+2j and b =3i+12j
In order for the two vectors to be perpendicular, the product of their slopes must be -1.
So slope of a = -2/x and slope of b = 12/3= 4
slope of a * slope of b = (-2/x)*4 = -1 so x = 8.

anonymous · Answer

I  think it is vector  product problem.

anonymous · Answer

By the way i forgot to mention how i got the slope.
It is the vertical component/horizontal component, that is 
slope =(coefficient of j/coefficient of i)

anonymous · Answer

And another way to do it is through dot product.
a.b = 0 since cos90 = 0
So (-3x)i+24j = 0 and taking the magnitude, and simplifying, we get x=8.

anonymous · Answer

@kartiksriramk  ah! you got me!

anonymous · Answer

This one looks good to me..

anonymous · Answer

@muhammad9t5  ;)

anonymous · Answer

When two vectors A and B are perpendicular then there dot product will be 0..

$$vectors(A \cdot B) = ABcos(90) = 0$$

anonymous · Answer

Thank you guys!

anonymous · Answer

You're welcome.