Q 1 :    

The zeroes of the polynomial x23xm(m+3) are

  • m,m+3

     

  • -m,m+3

     

  • m,-(m+3)

     

  • -m,-(m+3)

     

(2)

Let p(x)=x2-3x-m(m+3)

p(x)=x2-(m+3)x+mx-m(m+3)

=x{x-(m+3)}+m{x-(m+3)}

For zeros of p(x)

p(x)=(x+m){x-(m+3)}=0x=-m,m+3

 Its zeros are -m,m+3



Q 2 :    

If α and β are the zeros of a polynomial f(x)=px22x+3p and α + β = αβ, then p is

  • -2/3

     

  • 2/3

     

  • 1/3

     

  • -1/3

     

(2)

Given, f(x)=px2-2x+3p

Since α and β are the zeroes of the given polynomial.

 α+β=-(-2)p=2p, and αβ=3pp=3

 α+β=αβ      (given)

 2p=3p=23



Q 3 :    

The zeroes of a polynomial x2+px+q are twice the zeroes of the polynomial 4x25x6. The value of p is :

  • -5/2

     

  • 5/2

     

  • -5

     

  • 10

     

(1)

Given polynomials : x2+px+q   ...(i)

and 4x2-5x-6       ...(ii)

Zero of polynomial 4x2-5x-6 are: x=2 and x=-3/4

Now, zero of polynomial x2+px+q are 4 and -3/2

 Sum of zeroes =-p1

4-32=-p1-p=52p=-52



Q 4 :    

Assertion (A): If the graph of a polynomial touches x-axis at only one point, then the polynomial cannot be a quadratic polynomial.

Reason (R): A polynomial of degree n(n >1) can have at most n zeroes.

  • Both, Assertion (A) and Reason (R) are true and Reason (R) is correct explanation of Assertion (A).

     

  • Both, Assertion (A) and Reason (R) are true but Reason (R) is not correct explanation for Assertion (A).

     

  • Assertion (A) is true but Reason (R) is false.

     

  • Assertion (A) is false but Reason (R) is true.

     

(4)

The polynomials of the form (x+a)2 and (x-a)2 has only equal roots and graphs of these polynomials cut x-axis at only one point. These polynomials are quadratic Thus, Assertion is false Reason is true.

 



Q 5 :    

If the sum of zeroes of the polynomial p(x)=2x2-k2x+1 is 2, then value of k is :

  • 2

     

  • 2

     

  • 22

     

  • 1/2

     

(2)

Sum of zeroes =2=-(-k2)2k=2

 



Q 6 :    

If α and β are zeroes of the polynomial 5x2+3x7, the value of 1α+1β is

  • −3/7

     

  • 3/5

     

  • 3/7

     

  • −5/7

     

(3)

α+β=-ba=-35,  αβ=ca=-75

Now, 1α+1β=α+βαβ=-35-75=37

 



Q 7 :    

Assertion (A): If the graph of a polynomial intersects the x-axis at exactly two points, then the number of zeroes of that polynomial is 2.

Reason (R): The number of zeroes of a polynomial is equal to the number of points where the graph of the polynomial intersects x-axis.

  • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

     

  • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).

     

  • Assertion (A) is true, but Reason (R) is false.

     

  • Assertion (A) is false, but Reason (R) is true.

     

(1)     Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).