JAMB - Mathematics (1989 - No. 18)
Factorize completely \(y^3 -4xy + xy^3 - 4y\)
(y + xy)(y + 2)(y - 2)
(y - xy)(y - 2)
y(1 + x)(y + 2)(y -2)
y(1 - x)(y + 2)(y - 2)
Spiegazione
\(y^3 -4xy + xy^3 - 4y \)
= \(y^3(1 + x) - 4y(1 + x)
\((y^3 - 4y)(1 + x) = (y^3(1 + x) - 4y(1 + x))\)
∴ = \(y(1 + x)(y + 2)(y - 2)\)