Find a subset of the vectors that form a basis for the span of the vectors; then express each vector not in the basis as a linear combination of the basis vectors.
v1 = (1,1,-1,2), v2 = (1,-1,1,1), v3 = (3,-5,5,2), v4 = (6,2,-3,8), v5 = (8,2,-4,9)

The value √10 and √15 are plotted on the number line

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

It took alice 5 5/6 hours to drive to her grandparents' house for . on the way home, she ran into traffic and it took her 7 3/8 hours. how much longer did the return trip take? write your answer as a proper fraction or mixed number in simplest form. the trip home took __hours longer. ?