A.B.C.D.
A.B.C.D.有限值
A.當(dāng)r(A)=m時(shí),方程組有解B.當(dāng)r(A)=n時(shí),方程組有唯一解C.當(dāng)m =n時(shí),方程組有唯一解D.當(dāng)r(A)=r < n時(shí),方程有無窮多組解