[tex]\left\{\begin{array}{ccc}y-2x=1&|add\ 2x\ to\ both\ sides\\x+2y=27\\\end{array}\right\\\begin{array}{ccc}(1)\\(2)\end{array}\left\{\begin{array}{ccc}y=1+2x\\x+2y=27\\\end{array}\right\\\\\\subtitute\ (1)\ to\ (2)\\\\x+2(1+2x)=27\\x+2+4x=27\\5x+2=27\ \ \ |subtract\ 2\ from\ both\ sides\\5x=25\ \ \ \ |divide\ both\ sides\ by\ 5\\\boxed{x=5}\\\\subtitute\ the\ value\ of\ x\ to\ (1)\\\\y=1+2\cdot5\\y=1+10\\\boxed{y=11}\\\\Answer:\boxed{x=5\ and\ y=11}[/tex]
