Given A=(abcd)A = \begin{pmatrix} a & b \\ c & d \end{pmatrix}A=(acbd), which expression represents the characteristic equation?
λ2−(a+d)λ+(ad−bc)=0\lambda^2 - (a+d)\lambda + (ad-bc) = 0λ2−(a+d)λ+(ad−bc)=0
λ2+(a+d)λ+(ad−bc)=0\lambda^2 + (a+d)\lambda + (ad-bc) = 0λ2+(a+d)λ+(ad−bc)=0
λ2−(a+d)λ−(ad−bc)=0\lambda^2 - (a+d)\lambda - (ad-bc) = 0λ2−(a+d)λ−(ad−bc)=0
λ2+(a+d)λ−(ad−bc)=0\lambda^2 + (a+d)\lambda - (ad-bc) = 0λ2+(a+d)λ−(ad−bc)=0