mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">y</mi><mo>=</mo><mi mathvariant="normal">f</mi><mfenced separators="|"><mi mathvariant="normal">x</mi></mfenced><mo>=</mo><mfrac><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mn>2</mn></mrow><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mn>1</mn></mrow></mfrac></math>