Question

If one of the zero of the quadratic polynomial 2x2+kx-15 is 3 find the other zero and value of k

Answer 1

Hii there!!

Plz refer to the attachment for the solution.

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Answer 2

Answer:

Value of k = -1,

Value of k = -1,Other zero = 5/2

Step-by-step explanation:

Let p(x)=2x²+kx-15,

Given 3 is one zero of p(x).

Then ,

p(3)=0

=> 2(3²)+k(3)-15=0

=> 18+3k-15=0

=> 3k + 3 = 0

=> 3k = -3

Divide each term by 3 ,we get

=> k = -1

Put k = -1 , in p(x) , we get

p(x)= 2x²-x-15

Splitting the middle term, we get

= 2x²-6x+5x-15

= 2x(x-3)+5(x-3)

=(x-3)(2x-5)

Take 2x-5=0

=> x=5/2

Therefore,

Value of k = -1,

Other zero = 5/2

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