Odpowiedź:
[tex]a)\\\\\begin{cases}x+y=2\ \ |\cdot(-1)\\x+y=9\end{cases}\\\\\\+\begin{cases}-x-y=-2\\x+y=9\end{cases}\\---------\\0=7\\\\Uklad\ \ r\'owna\'n\ \ sprzeczny\ \ nie\ \ ma\ \ rozwiazania\\\\\\c)\\\\\begin{cases}2x-3y-7=0\\-2x+1,5y-4=0\end{cases}\\\\\\+\begin{cases}2x-3y=7\\-2x+1,5y=4\end{cases}\\----------\\-1,5y=11\ \ |:(-1,5)\\\\y=-11:1,5\\\\y=-11:\frac{15}{10}\\\\y=-11:\frac{3}{2}\\\\y=-11\cdot\frac{2}{3}\\\\y=-\frac{22}{3}\\\\y=-7\frac{1}{3}[/tex]
[tex]2x-\not3\cdot(-\frac{22}{\not3})=7\\\\2x+22=7\\\\2x=7-22\\\\2x=-15\ \ |:2\\\\x=-\frac{15}{2}\\\\x=-7\frac{1}{2}\\\\\\\begin{cases}x=-7\frac{1}{2}\\y=-7\frac{1}{3}\end{cases}[/tex]
