Question

7. Factor: 5x2 – 15x – 20.

(a) 5(x-4)(x+1),

(b) -2(x-4)(x+5),

(c) -5(x+4)(x-1),

(d) 5(x+4)(x+1).

Answer 1

Solution:

5x2 – 15x – 20.

= 5(x2 – 3x – 4).

= 5(x2 – 4x + x – 4).

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

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

Answer: (a).

Answer 2

Hello here ...

Question Given

$given \: \\ 5 {x}^{2} - 15x - 20 \\ \\ = > 5( {x}^{2} - 3x - 4) \\ \\ = > 5( {x}^{2} - 4x + x - 4) \\ \\ = > 5( {x}(x - 4) + 1(x - 4)) \\ \\ = > 5(x - 4)(x + 1)$
Option a is correct answer .✔
Hope it's helps you.
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