1.

If alpha and betaare the zeroes of thequadratic polynomial f(x) = x^2 -p ( x+ 1) -c , show that(α+ 1) (β + 1 ) = 1 - c​

Answer»

To ProvE :

  • (α+ 1) (β + 1 ) = 1 - c

SolutioN :

<P>\tt \dagger \:  \:  \:  \:  \: Sum \:  of  \: Zeros.

\tt \dagger \:  \:  \:  \:  \: \alpha  +  \beta  =  \dfrac{ - b}{a}

\tt \dagger \:  \:  \:  \:  \: product \:  of  \: Zeros.

\tt \dagger \:  \:  \:  \:  \:  \alpha  \beta  =  \dfrac{c}{a}

A/Q,

We have EQUATION,

\tt \dagger \:  \:  \:  \:  \:  {x}^{2}   - p(x  + 1) - c.

\tt  : \implies  {x}^{2}   - p(x  + 1) - c.

\tt \dagger \:  \:  \:  \:  \:  {x}^{2}   - px   -  p - c.

Compare with GENERAL Expression.

\tt \dagger \:  \:  \:  \:  \: a {x}^{2}  + bx + c

Where as,

  • a = 1.
  • b = -p
  • c = - p - c.

Now,

→ (α+ 1) (β + 1 )

→ αβ + α + β + 1.

  • Product of Zeros ( αβ ) → - p - c
  • Sum of Zeros ( α + β ) → p.

★ Putting the GIVEN value on it.

→ αβ + α + β + 1.

→ - p - c + p + 1.

→ - c + 1.

Hence Proved.



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