Question

Give zeroes of quadradie polynomial .2x - 15.
(A) 3 and 5
(B) -3 and 5
(3 and -5
(D) -3 and 5

Answer 1

Step-by-step explanation:

Factorise the given polynomial x

2

−2x−15 as shown below:

x

2

−2x−15=0

⇒x

2

−5x+3x−15=0

⇒x(x−5)+3(x−5)=0

⇒(x+3)=0,(x−5)=0

⇒x=−3,x=5

Therefore, the zeroes of the polynomial is x=−3,5.

The sum and product of the zeroes is:

Sum=−3+5=2.........(1)

Product=(−3)×(5)=−15.......(2)

Now, in general, we know that for a equation ax

2

+bx+c=0, if zero are α and β, plug the values of a, b and c we get,

Sum and product of the zeroes is:

Sum=−

a

b

=−

1

−(−2)

=2.......(3)

Product=

a

c

=

1

−15

=−15........(4)

Thus, equation 1 is equal to equation 3 and equation 2 is equal to equation 4.

Hence verified.

Answer 2

Question

• Give zeroes of quadradie polynomial .2x - 15.

Answer

• (B) -3 and 5