Bonjour je bloque cet exercice de maths (spe) je ne comprends pas du tout comment on fait, merci ceux qui m’aident mon devoir

Bonjour,

1)

[tex]\left[\begin{array}{cc}3&5\\4&10\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] =\left[\begin{array}{c}15\\24\end{array}\right] \\\\\\\left[\begin{array}{cc}3&5\\4&10\end{array}\right]^{-1}=\left[\begin{array}{cc}1&-\frac{1}{2}\\-\frac{4}{10} &\frac{3}{10}\end{array}\right]\\\\\\\left[\begin{array}{cc}1&-\frac{1}{2}\\-\frac{4}{10} &\frac{3}{10}\end{array}\right]\left[\begin{array}{c}15\\24\end{array}\right]=\left[\begin{array}{c}3&\frac{6}{5} \end{array}\right][/tex]

2)

[tex]\left[\begin{array}{cc}0.5&1\\0.3&1\end{array}\right] \left[\begin{array}{c}a\\b\end{array}\right] =\left[\begin{array}{c}102\\131\end{array}\right] \\\\\\\left[\begin{array}{cc}0.5&1\\0.3&1\end{array}\right]^{-1}=\left[\begin{array}{cc}5&-5\\-1.5&2.5\end{array}\right]\\\\\\\\\left[\begin{array}{cc}1&-\frac{1}{2}\\-\frac{4}{10} &\frac{3}{10}\end{array}\right]\left[\begin{array}{c}15\\24\end{array}\right]=\left[\begin{array}{c}3&\frac{6}{5} \end{array}\right][/tex]