Question

помогите с алгеброй 7 класс​

Answer 1

Ответ:

Все решение на фото

Объяснение:

Answer 2

Ответ:

$1)\ \ \left\{\begin{array}{l}2x+2y=8\\2x-2y=0\end{array}\right\ \ \ \ Otvet:\ (2;2)\ .\\\\\\2)\ \ \left\{\begin{array}{l}13x-8y=28\\-11x+8y=-24\end{array}\right\ \oplus \ \left\{\begin{array}{l}2x=4\\8y=11x-24\end{array}\right\ \ \left\{\begin{array}{l}x=2\\8y=-2\end{array}\right\ \ \left\{\begin{array}{l}x=2\\y=-0,25\end{array}\right\ \ (2;-0,25)$

$3)\ \ \left\{\begin{array}{l}3x+2y=5\\5x-2y=-45\end{array}\right\ \oplus \ \left\{\begin{array}{l}8x=-40\\2y=-3x+5\end{array}\right\ \ \left\{\begin{array}{l}x=-5\\2y=20\end{array}\right\ \ \left\{\begin{array}{l}x=-5\\y=10\end{array}\right\ \ (-5;10)$

$4)\ \ \left\{\begin{array}{l}y-x=20\ |\cdot 2\\-15y+2x=-1\end{array}\right\ \oplus \ \left\{\begin{array}{l}-13y=39\\x=y-20\end{array}\right\ \ \left\{\begin{array}{l}y=-3\\x=-23\end{array}\\ \ \ (-23;-3)$

$5)\ \ \left\{\begin{array}{l}x-4y=25\ |\cdot (-3)\\3x-2y=30\end{array}\right\ \oplus \left\{\begin{array}{l}10y=-45\\x=25+4y\end{array}\right\ \ \left\{\begin{array}{l}y=-4,5\\x=7\end{array}\right\ \ \ \ (7;-4,5)$