3. (2 points) Solve the system 4x1-5x2+3x3 +2x4 = 3 -x1 +x2+2x3+2x4 =5 3x1-4x2+5x3+4x4 = 8 2x1+2x2+4x3+4x4 =10 X1 X2 X3 XA 4. (2 points) The reduced row-echelon forms of the aug- mented matrices of four systems are given below. How many solutions does each system have? 1 0 -11 O 0 O (1) 0 0 O O O O . A. Unique solution . B. Infinitely many solutions . C. No solutions . D. None of the above 1 0 O (2) 0 1 8 O 0 0 O . A. No solutions . B. Unique solution . C. Infinitely many solutions . D. None of the above 0 1 0 -15 (3) 0 0 1 13 . A. Infinitely many solutions . B. No solutions . C. Unique solution . D. None of the above (4) 6 9 3 . A. Unique solution . B. Infinitely many solutions . C. No solutions