True-false questions: justify your answers. 1.13 the solution set to a system of three equations in three unknowns cannot be a 1.14 a system of linear equations cannot have only two solutions. plane. 1.15 the solution set to a consistent rank 2 linear system in four unknowns would 1.16 a system of four equations in four unknowns always has a solution. 1.17, a system of four equations in four unknowns can have at most one solution be a line in four-dimensional space. 1.18 the rank of a system is always less than or equal to the number of equations in the systemm