Factor polynomials that can be factored as the product of a monomial and a quadratic expression, then further factor the quadratic expression.

Problem

Factor the polynomial expression completely.
28, y, start superscript, 4, end superscript, plus, 7, y, start superscript, 3, end superscript, minus, 21, y, start superscript, 2, end superscript, equals
Get 3 answers correct in a row