Question

Find the following product: (y² − 4) (y² − 3)

Answer 1

Here, we will use the identity​ \[\left( x - a \right)\left( x - b \right) = x^2 - \left( a + b \right)x + ab\].

\[\left( y^2 - 4 \right)\left( y^2 - 3 \right)\]

\[ = \left( y^2 \right)^2 - \left( 4 + 3 \right)\left( y^2 \right) + 4 \times 3\]

\[ = y^4 - 7 y^2 + 12\]