Question

gente me ajuda por favor eu não sei fazer essa conta então por favor quem sabe me ajuda ... ela é assim
metodo de adição

a x-y + = 14
x-y =2

b 2x -( y -1 ) =4
x+3y=5

Answer 1

$A)~~ \begin{cases}x+y=14\\ x-y=2\end{cases}\\\\\\\\ x+y=14\to~~ x=-y+14\\\\\\ x-y=2\to~~-y+14-y=2\to~~ -y-y=2-14\to\\\\ -2y=-12~(-1)\to~~2y=12\to~~y= \dfrac{12}{2} \to~~ \large\boxed{y=6}\\\\\\\\ x=-y+14\to~~ x=-6+14\to~~ \large\boxed{x=8}\\\\\\\\\\ \Large\boxed{\boxed{S=\left\{ 8~;~6 \right\}}}$





$B)~~\begin{cases}2x -( y -1 ) =4 \\ x+3y=5\end{cases}\\\\\\\\ x+3y=5\to~~x=-3y+5\\\\\\\\ 2x -( y -1 ) =4\to~~ 2(-3y+5) -( y -1 ) =4\to\\\\ -6y+10-y+1=4\to~~ -6y-y=4-10-1\to\\\\-7y=-7~(-1)\to~~7y=7\to~~y= \dfrac{7}{7} \to~~\large\boxed{y=1}\\\\\\ x=-3y+5\to~~x=-3.1+5\to~~ x=-3+5\to ~~\large\boxed{x=2}\\\\\\\\\\ \Large\boxed{\boxed{S=\left\{ 2~;~1 \right\}}}$