Question

Ajude me a resolver, as questões 40,41 e 42, e pra entregar hoje!

Answer 1

$Ola'~~ \\ \\ 40) ~~a=\begin{vmatrix}2&1 \\ -3&4\end{vmatrix}~=\ \textgreater \ a=8+3=\boxed{11} \\ \\ ~~~~~~~b=\begin{vmatrix}21&7 \\ -3&1\end{vmatrix}}~=\ \textgreater \ b=21+21=\boxed{42} \\ \\ ~~~~~~~c=\begin{vmatrix}-1&-2 \\ 5&3\end{vmatrix}~=\ \textgreater \ c=-3+10=\boxed{7} \\ \\ A=a\²+b\²-c\² \\ \\ A=11\²+42\²-7\² \\ \\\boxed{\boxed{ A=1836}} \\ \\ ====================================$

$41)~\begin{vmatrix}x&x \\ 5&x\end{vmatrix}=-6 \\ \\ x\²-5x+6=0 \\ \\ (x-3).(x-2)=0 \\ \\ \therefore ~\begin{cases}x_1=3 \\ x_2=2\end{cases} \\ \\ ================================== \\ 42)~~A=\begin{vmatrix}2&3 \\ 3&4\end{vmatrix}~~=\ \textgreater \ A=8-9=\boxed{-1} \\ \\ Determine~: A\²-2A=(-1)\²-2(-1)=3 \\ \\\therefore~~ \boxed{\boxed{A\²-2A=3}}$


$\mathbb{iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii} \\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Eespero~ter~ajudado!!$