Question

5x2 – 15x – 20. (a) 5(x-4)(x+1),

Answer 1

$1. {5x}^{2} - 15 - 20$

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

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

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

5{x(x - 4) +1(x - 4)}.

= 5(x-4)(x+1).