Question

If the sum of zeroes of a given polynomial f(x)=x^3-3kx^2-x+30 is 6 find the value of k

Answer 1

Hi ,

f( x ) = x³ -3kx² - x + 30

compare f ( x ) with ax³ + bx² + cx + d ,

a = 1 , b = -3k , c = -1 , d = 30

we know that ,

sum of the zeroes = - b/a

but according to the problem given ,

-b/a = 6

- ( -3k ) / 1 = 6

3k = 6

k = 6/3

k = 2

I hope this helps you.

:)

Answer 2

sum of the zeroes is 6 f(x)= x
$x^{2} - 3kx^{2} -x + 30$
sum of the zeroes =
$\alpha + \beta + \gamma = - b \div a$
3k/1=6
3k= 6
k=2