Find the greatest common factor of 39v and 30uv

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

I’m still confused on how to work the percentages

Sketch the vector field vector f( vector r ) = 8vector r in the xy-plane. select all that apply. the length of each vector is 8. the lengths of the vectors decrease as you move away from the origin. all the vectors point away from the origin. all the vectors point in the same direction. all the vectors point towards the origin. the lengths of the vectors increase as you move away from the origin.