Consider the sets of vectors of the following form. Determine whether the sets are subspaces of R3. If a set is a subspace, give a basis and its dimension. (Enter your basis as a comma-separated list. Enter each vector in the form (x1, x2, ...). If a set is not a subspace, enter NA for its basis and dimension.)
How do I go about this last one?
(c) (a, b, 4) basis NA dimension NA
(d) (a, a, a + 5) (1.16)x basis dimension1

Tom is the deli manager at a grocery store. he needs to schedule employee to staff the deli department for no more that 260 person-hours per week. tom has one part-time employee who works 20 person-hours per week. each full-time employee works 40 person-hours per week. write and inequality to determine n, the number of full-time employees tom may schedule, so that his employees work on more than 260 person-hours per week. graph the solution set to this inequality.