︱3a-b+1︱+〖（3a-3/2 b）〗^2=0，3a-b+1=0且（3a-3/2 b）=0解得 a= -1 ,b= -2b^2/(a+b)÷【(b/(a-b))×(ab/(a+b))】=b²/(a+b) × (a+b)(a-b)/ab²=(a-b)/a=( -1+2)/(-1)= -1
