Question

factorise.
– 7x² – 14x + 56​

Answer 1

Step-by-step explanation:

$- 7 {x}^{2} - 14x + 56 \\ \\ div \: by \: - 7 \\ \\ {x}^{2} + 2x - 8 \\ \\ {x}^{2} + 4x - 2x - 8 \\ \\ x(x + 4) - 2(x + 4) \\ \\ (x - 2)(x + 4)$

To find the root of the equation

Take

$x - 2 = 0 \: \: \: \: and \: \: \: \: x + 4 = 0 \\ \\ x = 2 \: \: \: \: \: and \: \: \: \: \: x = - 4$

Answer 2

Question :-

Factorise It ,

$\implies \: - 7 {x}^{2} - 14x + 56$

Answer :-

→ 2 and -4 are the factors of this quadratic.

Explanation :-

$\implies \: - 7 {x}^{2} - 14x + 56 = 0 \\ \\ \implies \: - 7 \big( {x}^{2} + 2x - 8 \: \big) = 0 \\ \\ \implies - 7 \big( {x}^{2} + 4x - 2x - 8x \: \big) = 0 \\ \\ \implies \: {x}(x + 4) - 2(x + 4) = 0 \\ \\ \implies \: \: (x + 4)(x - 2) = 0 \\ \\ \: \star \: case \: (1) \\ \\ \implies \: x + 4 = 0 \\ \\ \implies \: \boxed{x \: = - 4} \\ \\ \star \: case \: (2) \\ \\ \implies \: x \: - 2 = 0 \\ \\ \implies \: \boxed{x \: = 2}$