Question

factorise
$2x {}^{3} - 7x - 15$
​

Answer 1

★Question -

factorise 2x² -7x-15

★Answer-

by middle term splitting

2x² -7x -15

= 2x² -10x+3x+15

2x(x -5) +3(x-5)

$\rm\pink{(2x+3)(x+5)}$

★Additional Information -

$\rm Algebraic\: identities\\ \\ \\ \implies (a+b)^2 = a^2+b^2+2ab\\ \\ \\\implies (a-b)^2 = a^2+b^2 -2ab\\ \\ \\ \implies (a+b)(a-b) = a^2-b^2\\ \\ \\ \implies (a+b+c)^2 = a^2+b^2+c^2+2(ab+bc+ca)\\ \\ \\ \implies (a+b)^3 = a^3+b^3+3ab(a+b) \\ \\ \\ \implies a^3+b^3+c^3 = 3abc, if\:a+b+c= 0$

Answer 2

Answer:

★ Hence, after factorisation of 2x^3 - 7x - 15, we get, = 2x•(x^2 - 5) + 3•(x - 5)

Step-by-step explanation:

★ Given,

➡ P(x) = 2x^3 - 7x - 15

★ To Find :

➡ The value of 'x'.

★ Solution :

➡ P(x) = 2x^3 - 7x - 15

By using the method os splitting the middle term, we get,

➡ P(x) = 2x^3 - 10x + 3x - 15

➡ 2x^3 - 10x + 3x - 15 = 0

➡ 2x•(x^2 - 5) + 3•(x - 5) = 0

• Since, there is no common like terms within the numbers of expression, this is the final factorised step.

★ Hence, after factorisation of 2x^3 - 7x - 15, we get, = 2x•(x^2 - 5) + 3•(x - 5)