Use polynomial division to rewrite the equation
Generic Rectangle, 2 rows, 3 columns, with expression, 3 x squared, minus 5 x, minus 20, below the rectangle. Left edge labeled, x minus 4, interior top left, labeled 3 x squared.
Labels added: top edge left, 3 x, interior bottom left, negative 12 x.
Label added: Interior top middle, 7 x.
Labels added: top edge middle, 7, interior bottom middle, negative 28.
Continue the division problem. Part of the rewritten equation is a vertical asymptote, part is a slant asymptote.