What is 3.8+6x=8.6;x=0.9

Brook states that the distance on the line is 4 units. caleb states that the whole line does not have a distance because it continues on forever. vivian states that the line is 6 units long. which distance did brook measure? which distance did vivian measure?

Me. i can't figure out this question. give an explanation too. .

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities