Question

!!QUESTION FOR BRAINLY STARS!!

factorise : (x^2-3x)(x^2-3x-1)-20
plzz answer fast.....

Answer 1

take
${x}^{2} - 3x = y$

now the polynomial becomes

$y(y - 1) - 20$

${y}^{2} - y - 20$

$(y - 5)(y + 4)$

that is
$( {x}^{2} - 3x - 5)( {x}^{2} - 3x + 4)$