Vectors (1 Viewer)

[qwerla]

hey!!! I was wondering if anyone knew how to solve part B for this question. I can't seem to wrap my head around it. The answer is x= -3.
Thank you!!

 

[yanujw]

If it's parallel to the x-axis then there is no vertical component to the vector -> the coefficient of j is 0.
xa + 4b = (-13x + 8)i + (20x + 60)j
20x + 60 = 0
x = -3

 

[qwerla]

If it's parallel to the x-axis then there is no vertical component to the vector -> the coefficient of j is 0.
xa + 4b = (-13x + 8)i + (20x + 60)j
20x + 60 = 0
x = -3

thank you so much!