Intermediate Algebra (12th Edition)

$(y^2-6)(x^2+5)$
To factor means to convert an expression into expressions that are multiplied. The given expression, $x^2(y^2-6)+5(y^2-6) ,$ are not expressions that are multiplied. To factor this, factor the common expression, $(y^2-6)$. This results to \begin{array}{l}\require{cancel} (y^2-6)(x^2+5) .\end{array}