Question

48. If p and q are the zeros of the
polynomial 2 x^2 + 5 x-9, then the
value of pq is​

Answer 1

Answer :

pq = -9/2

Note:

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

★ A quadratic polynomial can have atmost two zeros .

★ The general form of a quadratic polynomial is given as ; ax² + bx + c .

★ If α and ß are the zeros of the quadratic polynomial ax² + bx + c , then ;

• Sum of zeros , (α + ß) = -b/a

• Product of zeros , (αß) = c/a

Solution :

Here ,

The given quadratic polynomial is ;

2x² + 5x - 9 .

Comparing the given quadratic polynomial with the general quadratic polynomial ax² + bx + c , we have ;

a = 2

b = 5

c = -9

Also ,

It is given that , p and q are the zeros of the given quadratic polynomial .

Now ,

=> Product of zeros = c/a

=> pq = -9/2

Hence , pq = -9/2

Answer 2

$\huge{ \underline{ \underline{ \blue{ \mathfrak { answer \: : - }}}}}$

Question:-

If p and q are the zeros of the polynomial 2 x^2 + 5 x-9, then the value of pq is?

Given:-

• Given equation is quadratic polynomial...

• Standard form of quadratic equations as ax²+bx+c=0 where a,b,c are real numbers and a≠0.

• The name Quadratic has been derived from the word "quadrate" which means"square".

Quadratic equation:-

A polynomial of degree 2 is called as quadratic equations.

$\huge {\underline{\underline\mathfrak \blue{solution : - }}}$

$\huge \sf\longmapsto \: {2x}^{2} + 5x - 9$

Compare with standard form of quadratic equations...

$\large\sf\longmapsto \: a = 2 \\ \\ \large \sf\longmapsto \:b = 5 \\ \\ \large \sf\longmapsto \:c = -9$

P and Q are the zeroes of the polynomials...

we know that,

$\huge \sf\longmapsto \:pq = \frac{c}{a}$

$\huge \sf\longmapsto \:pq = \frac{-9}{2}$