Question

Calcule os determinantes:

-3 2
3 -4

8 3
5 4

0 ¼
4 1


¾ -5

1/5 8

Answer 1

Olá

$\left[\begin{array}{ccc}-3&2\\3&-4\\\end{array}\right] =((-3)\cdot(-4))-(3\cdot2)=12-6=\boxed{6}$



$\left[\begin{array}{ccc}8&3\\5&4\\\end{array}\right]=(8\cdot 3)-(5\cdot3)=24-15=\boxed{9}$



$\left[\begin{array}{ccc}0& \frac{1}{4} \\4&1\\\end{array}\right]=(0\cdot1)-(\mathtt{\diagup\!\!\!\!4\cdot \frac{1}{\diagup\!\!\!\!\!4} )}=0-1=\boxed{-1}$



$\left[\begin{array}{ccc} \frac{3}{4} &-5\\ \\ \frac{1}{5} &8\\\end{array}\right]=\mathtt{ (\frac{3}{\diagup\!\!\!\!4}\cdot\diagup\!\!\!\!8)-( \frac{1}{\diagup\!\!\!\!5}\cdot-\diagup\!\!\!\!5 ) } \\ ~~~~~~~~~~ ~~~~~~~=(3\cdot2)-(-1)=6+1=\boxed{7}$