Question

If one zero of polynomial 3x2-8x+2k+1 is 7 times the other find d vlue of k..?

Answer 1

3x^2-8x+2k+1 a=3,

b=-8 ,c=2k+1

let assume the zero of the eqn are x and y , and  by using given idea, x=7y

as we know , x+y=-b/a

7y+y=-(-8)/3

8y=8/3

y=8/3×1/8=1/3

xy=c/a

7y*y=2k+1/3

7×1/3×1/3=2k+1/3

-->7/9=2k+1/3

-->21/9=2k+1

-->21/9-1=2k

-->12/9=2k

-->4/3=2k

-->4/6=k

-->2/3=k

or k=2/3