Răspuns:
Explicație pas cu pas:
det(A)=(1+5x)·(1-4x)-(-2x)·10x=1-4x+5x-20x²+20x²=1+x, deci 1+x=1, deci x=0
[tex]A(1)=\left[\begin{array}{ccc}1+5*1&10*1\\-2*1&1-4*1\\\end{array}\right] =\left[\begin{array}{ccc}6&10\\-2&-3\\\end{array}\right] \\(A(1))^{2}=\left[\begin{array}{ccc}6&10\\-2&-3\\\end{array}\right] *\left[\begin{array}{ccc}6&10\\-2&-3\\\end{array}\right] =\left[\begin{array}{ccc}6*6+10*(-2)&6*10+10*(-3)\\-2*6+(-3)*(-2)&-2*10+(-3)*(-3)\\\end{array}\right] =\left[\begin{array}{ccc}16&30\\-6&-11\\\end{array}\right][/tex]
