Question

If one zero of the polynomial -2x² +3kx-10 is 1 then value of k will be ........​

Answer 1

Answer:

k = 4

Step-by-step explanation:

Polynomial = - 2x² +3kx - 10

Zero of polynomial = 1

Put the value of x 1 in the polynomial

If 1 is the zero of polynomial then when we put the value of x 1 the solution of polynomial will be 0

- 2x² +3kx - 10 = 0

- 2 × ( 1 )² + 3k × 1 - 10 = 0

- 2 × 1 +3k -10 = 0

- 2 + 3k = 10

3k = 10 + 2

k = 12 / 3

k = 4

Answer 2

Answer :

k = 4

Note :

★ The possible values of the variable for which the polynomial becomes zero are called its zeros .

★ If x = a is a zero the polynomial p(x) then p(a) = 0 .ie ; the value of the polynomial at x = a will be zero .

Solution :

Here ,

The given quadratic polynomial is ;

-2x² + 3kx - 10 .

Let the given quadratic polynomial be p(x) .

Thus ,

p(x) = -2x² + 3kx - 10 .

Also ,

It is given that , x = 1 is a zero of the given quadratic polynomial p(x) , thus the value of the polynomial at x = 1 must be zero .

Thus ,

=> p(1) = 0

=> -2•1² + 3k•1 - 10 = 0

=> -2 + 3k - 10 = 0

=> 3k - 12 = 0

=> 3k = 12

=> k = 12/3

=> k = 4

Hence , k = 4 .