1.

Find the zeros of the quadratic polynomial 5x^2+12x+7and verify the relationship between the zeros and the coefficients

Answer»

\mathfrak{\large{\underline{\underline{<klux>GIVEN</klux>:-}}}}

Quadratic eqn:- \bold{ 5 {x}^{2}  + 12x + 7}

\mathfrak{\large{\underline{\underline{To find:-}}}}

Relation between their ZEROS and coefficient.

\mathfrak{\large{\underline{\underline{Solution:-}}}}

Let a = 5 , b = 12 and c = 7

Let \alpha and \beta be the roots of the given quadratic equation.

By USING MIDDLE splitting term,

\implies \bold{5 {x}^{2}  + 12x + 7}

\implies \bold{ 5 {x}^{2}  + 5x + 7x + 7= 0}

\implies \bold{5x( x + 1) + 7(x + 1) = 0}

\implies \bold{(5x + 7)(x + 1) = 0 }

\implies \bold{x =  \frac{ - 5}{7} or \: x =  - 1 }

Now, \alpha = \frac{ - 5}{7} and \beta = -1

The relationship between sum of zeroes and coefficient of Quadratic polynomial is given by :-

\boxed{\sf{ \alpha  +  \beta  =  \frac{ - b}{a} }}

\implies \bold{ \frac{ - 5}{7}  + 1 =  \frac{ - 12}{5} }

\implies\bold{   \frac{ - 7 - 5}{ 5} = \frac{ - 12}{5}  }[/tex][tex]\implies\bold{ \frac{-12}{5}  =  \frac{-12}{5} }

L. H. S = R. H. S verified.

Now,

Relation between products of zeroes and their coefficient is given by :-

\boxed{\sf{ \alpha  \beta  =  \frac{c}{a}   }}

\implies \bold{  \frac{ - 7}{5} \times  - 1  =  \frac{7}{5} }

\implies \bold{ \frac{7}{5}  =  \frac{7}{5} }

L. H. S = R. H. S hence ,verified..



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