Question

if f(x) = 3x³ + kx - 8 and 2 is a zero of f (x) then the value of k is​

Answer 1

Answer:

2

Explanation

f(x)=f(x)=x

4

−x

3

−8x

2

+kx+12

If 3 is the zero of f(x),then,

f(3)=0

=3

4

−3

3

−8(3)

2

+k(3)+12

=81−27−72+3k+12

=93−99+3k

=>3k=6

=>k=2

Answer 2

k = - 8

Step-by-step explanation:

Q.

If f(x) = 3x³ + kx - 8, and 2 is a zero of f(x), then value of k is,

Solution -

If

f(2) = 0 for f(x)

So,

f(2) = 3(2)³ + k(2) - 8 = 0

=> 3×2³ + 2k - 8 = 0

=> 3×8 + 2k - 8 = 0

=> 24 - 8 + 2k = 0

=> 16 + 2k = 0

=> 2k = - 16

=> k = -16/2

=> k = -8

So, the value of k is -8

hope it helps.