Question

If (3x-2) is a factor of 3x^3+kx^2-21x+10. Find the value of k and factorise this completely

Answer 1

Answer:

Step-by-step explanation:

f(x)=3x³+kx²-21x+10

g(x)=3x-2

so, x=2/3

f(2/3)=3*(2/3)³+k*(2/3)²-21*(2/3)+10=0

       =3*8/27+k*4/9-14+10=0

       =8/9+4k/9-4=0

       =8/9+4k/9=4

       =4k/9=4-8/9

       =4k/9=28/9

       =k=28/9*9/4

       =k=7

so. k=7