- Home
- Standard 9
- Mathematics
2. Polynomials
medium
Factorise $: x^{3}+x^{2}-26 x+24$
Option A
Option B
Option C
Option D
Solution
Sum of all the coefficients of terms of the polynomial
$=1+1-26+24$
$=26-26=0$
So, $(x-1)$ is a factor of $p(x)$
$x^{3}+x^{2}-26 x+24$
$=\underline{x^{3}}-x^{2}+\underline{2 x^{2}-2 x}-\underline{24 x+24}$
[Splitting the terms to get $x-1$ as a factor.]
$=x^{2}(x-1)+2 x(x-1)-24(x-1)$
$=(x-1)\left(x^{2}+2 x-24\right)$
$=(x-1)\left(x^{2}+6 x-4 x-24\right)$
[By splitting the middle term]
$=(x-1)[x(x+6)-4(x+6)]$
$=(x-1)(x+6)(x-4)$
Standard 9
Mathematics