Question

Find the zeros of the polynomial f(x)=x^3-5x^2-2x+24 if it is given that the product of its two zweroes is 12

Answer 1

Hi mate,

solution: x³-5x²-2x+24

compare with ax³+bx²+cx+d

α+β+y=-b/a

=5

αβy=-d/a

=-24

12y= -24

(as given the product of two. zeros ie αβ=12)

y= -2.

α+β+y=5

α+β-2=5

α+β =7. .................(1)

(α+β)²=7²

(α-β)²+4αβ=49

(α-β)²+4*12=49

(α-β)²+48= 49

(α-β)² =1

α-β = √1

α-β=1. ....................(2)

subtracting (2) From (1)

α+β-(α-β)=7-1

α+β-α+β=6

2β =6

β=3

putting the value of β in the (2) eq

α-3=1

α=4

α=4,β=3,y=-2

product of α and β = 4 * 3 = 12

I hope it helps you..