[tex]x-4y=11\ /\cdot(-5)\\5x-7y=-10 \\\\-5x+20y=-55\\5x-7y=-10\\--------\\-5x+20y+5x-7y=-55-10\\13y=-65\ /:13\\y=-5\\\\[/tex]
[tex]x-4y=11\ /\cdot7\\5x-7y=-10\ /\cdot(-4) \\\\7x-28y=77\\-20x+28y=40\\---------\\7x-28y-20x+28y=77+40\\-13x=117\ /:(-13)\\x=-9\\\\Ans.\ \ x=-9\ \ and\ \ y=-5[/tex]
