Question

factorise the following
$2y {}^{3} - 5y ^{2} - 19y + 42$

Answer 1

$\mathit{\huge{\pink{ANSWER:-}}}$

$\mathbf{\large{\green{2y{}^{3}-5y^{2}-19y+42}}}$

$\\=\mathbf{\large{\green{ 2y {}^{3} - 4y {}^{2} - {y}^{2} + 2y - 21y + 42 \\ = 2y {}^{2} (y - 2) - y(y - 2) - 21(y - 2) \\ = (y - 2)(2y {}^{2} - y - 21) \\ = (y - 2)( {2y}^{2} + 6y - 7y - 21) \\ = (y - 2)(2y(y + 3) - 7(y + 3)) \\ = (y - 2)(y + 3)(2y - 7) \:}}} ans.. \:$

$\textbf{\large{\blue{Hope it helps}}}$