Question

Sabendo que as matrizes A e B são iguais, o valor de x - y é: *​

Answer 1

$\large\begin{bmatrix}\sf x+3&\sf11\\\sf9&\sf2y-7\end{bmatrix}=\begin{bmatrix}\sf-5&\sf11\\\sf9&\sf13\end{bmatrix}\\\sf x+3=-5\\\sf x=-3-5\\\sf x=-8\\\sf 2y-7=13\\\sf 2y=13+7\\\sf2y=20\\\sf y=\dfrac{20}{2}\\\sf y=10\\\sf x-y=-8-10\\\sf x-y=-18$