Odpowiedź:
[tex]a)\\\\\begin{cases}2(x-3)+3(y-5)=4(x-1)-3(y-7)\\2(x+y)-5(y-x)=3(2x-y)+5(5x-3y)\end{cases}\\\\\\\begin{cases}2x-6+3y-15=4x-4-3y+21\\2x+2y-5y+5x=6x-3y+25x-15y\end{cases}\\\\\\\begin{cases}2x-21+3y=4x+17-3y\\7x-3y=31x-18y\end{cases}\\\\\\\begin{cases}2x+3y-4x+3y=17+21\\7x-3y-31x+18y=0\end{cases}\\\\\\\begin{cases}-2x+6y=38\ \ /:(-2)\\-24x+15y=0\ \ /:3\end{cases}\\\\\\\begin{cases}x-3y=-19\ \ /*8\\-8x+5y=0\end{cases}[/tex]
[tex]+\begin{cases}8x-24y=-152\\-8x+5y=0\end{cases}\\----------\\-19y=-152\ \ /:(-19)\\y=8\\\\\\-8x+5*8=0\\\\-8x+40=0\\\\-8x=-40\ \ /:(-8)\\\\x=5\\\\\begin{cases}x=5\\y=8\end{cases}\\\\\\\\b)\\\\\begin{cases}\frac{2x}{3}+\frac{4y}{5}=-2\ \ /*15\\\frac{x}{2}-\frac{y}{10}=2\ \ /*10\end{cases}\\\\\\\begin{cases}10x+12y=-30\ \ /:(-2)\\5x-y=20\end{cases}\\\\\\+\begin{cases}-5x-6y=15\\5x-y=20\end{cases}\\---------\\-7y=35\ \ /:(-7)\\y=-5[/tex]
[tex]5x-(-5)=20\\\\5x+5=20\\\\5x=20-5\\\\5x=15\ \ /:5\\\\x=3\\\\\begin{cases}x=3\\y=-5\end{cases}[/tex]
