dont understand this can someone help me

[tex]\bf \textit{when x = -2} \\\\\\ y=3x^2-x\implies y=3(-2)^2-(-2)\implies y=3(4)+2\implies y=14 \\\\\\ \textit{when x = 3} \\\\\\ y=3x^2-x\implies y=3(3)^2-(3)\implies y=3(9)-3\implies y=24 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \begin{array}{l|llllllll} x&-3&-2&-1&0&1&2&3\\\\ y&30&\boxed{14}&4&0&2&10&\boxed{24} \end{array}[/tex]