Linear Algebra

Need help in Linear Algebra Homework.
Lecture 3
Vector spaces and subspaces
Solving Ax = 0 and Ax=b
Upper triangular matrices (U) and Row reduced echelon form (R)
Converting Ax=b to Ux=c to Rx=d
Null space solutions or special solutions and particular solutions
Lecture 4
Linear independence and dependence of vectors
The four fundamental subspaces
Linear Transformations
Also attached PDF file at the end of the lecture there’s homework section of 5 questions in each pdf.
Please help me .