Given A, R105, denote the j-th column in A as a, i.e., A = [a1, a2, a3, a4, as].
For the linear equation A = b to be valid, A should have 5 components, and b should have 5 components.
If b = a + 7a5, then A = b is guaranteed to have a special solution. (Input all the elements in A, separated only by a comma, do not omit any elements) (Hint for students who did not learn this earlier: A is a linear combination of columns in A, and the given b is already a linear combination of columns in A) For this special solution to be unique, the A must have 5 linearly independent columns (so that Null(A) can only contain the zero vector).
If A has only three linearly independent columns, then rank(A) = [type your answer], dim(Null(A)) = [type your answer], dim(Range(A)) = [type your answer]. In this case, can Ax = b have a unique solution for any vector b? [type your answer] (input only yes or no)