[tex]x = -3, \ y = -4\\3x-5y = 3\cdot(-3)-5\cdot(-4) = -9+20 = 11\\\\A. \ 6-x-y = 6-(-3)-(-4) = 6+3+4 = 13\neq -13\\\\B. \ 2x+3y = 2\cdot(-3)+3\cdot(-4) = -6-12 = -18\neq 18\\\\C.\\2x-y = 2\cdot(-3) - (-4) = -6+4 = -2\\y+x+5 = -4+(-3)+5 = -7+5 = -2\\-2 = -2\\\\D. \ x+y-7 = (-3)+(-4)-7 = -3-4-7 = -14 \neq 0\\\\Odp. \ C.[/tex]
