Question

If two roots of a cubic polynomial x
3 − ax
2 − bx + 60 are 4 and 5. Which of the following is the

third root of the given polynomial? (Note: we don’t need to find values of a and b here)
(A) −5 (B) −4 (C) 3 (D) −3

Answer 1

Answer:

-3

Step-by-step explanation:

hey mate

we know the relation,

In a cubic polynomial,

product of the roots=-d/a

in a standard form ax³+bx+c+d where a,b,c,d are real no.s and a≠0

therefore,

product of the roots= -60/1

=>ß*4*5=-60

=>ß=-3

hence,the third root is -3..

some additional information:

*an algebric expression in which atleast a variable involved has highest power of 3.that is the degree of polynomial is 3.

*in a cubic equation:

sum of the roots taken one at a time=-b/a

sum of the roots taken 2 at a time=c/a

product of the roots=-d/a

where a,b and c are the coefficient of x³,x² and x respectively and d is the constant term....