Question

Factorise 3x^3-5x^2-58x+40

Answer 1

Answer:

(x+4)(3x-2)(x-5)

Step-by-step explanation

3x³-5x²-58x+40

Taking x=-4

3(-4)³-5(-4)²-58(-4)+40

3(-64)-5(16)-58(-4)+40

-192-80+232+40

0

(x+4) is one of the root

3x³-5x²-58x+40

3x²(x+4)-17x²-58x+40

3x²(x+4)-17x(x+4)+10x+40

3x²(x+4)-17x(x+4)+10(x+4)

(x+4)(3x²-17x+10)

(x+4)(3x²-15x-2x+10)

(x+4)[3x(x-5)-2(x-5)]

(x+4)(3x-2)(x-5)