What is the greatest common factor of 30 and 90

a: 6
b: 18
c: 36
d: 180

make sure to do the process of elimination, and the answer you choose make sure to explain why you choose i will

give brainelist and it worth alot im going on vacation tomorroww i've been stuck on this for days

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field