If the system of linear equations x1+2x2+3x3=6,x1+3x2+5x3=9,2x1+5x2+ax3=bis consistent and has infinite number of solutions, then

Augmented Matrix =1236135925ab                                  Apply R2→R2-R1;R3→R3-2R1                                 ~1236012301a-6b-12                                      Apply R3→R3-R2                                  ~1236012300a-8b-15Thus,if a=8 and b=15,then the system is consistent, with an infinite no. of solutions.