Question

factorise -: x^3+13x^2+31x-45

factorise this by using middle term spilliting of cubes..

help me guys​

Answer 1

Answer:

(x-1)(x² +14x +45)

Step-by-step explanation:

x³ + 13² +31x - 45

1.Find a suitable replacement for x so that the equation is equal to zero

N.B : you cannot use zero as the replacement of x

use values like -1; 1 ;-2;2 ;-3; 3 .......etc

in this case we'll use 1

i.e

(1)³ +13(1)² +31(1) -45

⇒45-45 = 0

since x=1 ⇒ (x-1) = 0

2. Now factorise using (x-1) as the main factor

x²(x-1) + 14x (x-1) + 45(x-1)

⇒(x-1)(x²+14x+45)