Factor the following trinomials completely.
$y^2-7y+12$

$\(\left\)(y+3\(\right\))\(\left\)(y-4\(\right\))$

$\(\left\)(y-3\(\right\))\(\left\)(y-4\(\right\))$

$\(\left\)(y+7\(\right\))\(\left\)(y-1\(\right\))$

$\(\left\)(y-1\(\right\))\(\left\)(y-12\(\right\))$