The number of real roots of 32 x2-7 x-7-9 is-A- 4B- zeroC- 2D- 1

The correct option is C 23^2x^2 7x+7=9 ⇒ 3^2x^2 7x+7 =3^2 ⇒ 2^x^2 7x+7=2 ⇒ 2^x^2 7x+5=0 Here Discriminant =( 7)^2 4(2)(5)=49 40=9 0 Hence the given equation ha ...

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Standard XII

Mathematics

Discriminant

The number of...

Question

The number of real roots of $3^{2 x^{2} - 7 x + 7} = 9$ is :

zero

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Solution

The correct option is B 2
$3^{2 x^{2} - 7 x + 7} = 9 \Rightarrow 3^{2 x^{2} - 7 x + 7} = 3^{2}$
$\Rightarrow 2^{x^{2}} - 7 x + 7 = 2 \Rightarrow 2^{x^{2}} - 7 x + 5 = 0$
Here Discriminant $= (- 7)^{2} - 4 (2) (5) = 49 - 40 = 9 > 0$
Hence the given equation has two real roots.

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The number of real roots of 32x2−7x+7=9 is :

The correct option is B 232x2−7x+7=9⇒32x2−7x+7=32 ⇒2x2−7x+7=2⇒2x2−7x+5=0 Here Discriminant =(−7)2−4(2)(5)=49−40=9> 0 Hence the given equation has two real roots.

The number of real roots of $3^{2 x^{2} - 7 x + 7} = 9$ is :

The correct option is B 2
$3^{2 x^{2} - 7 x + 7} = 9 \Rightarrow 3^{2 x^{2} - 7 x + 7} = 3^{2}$
$\Rightarrow 2^{x^{2}} - 7 x + 7 = 2 \Rightarrow 2^{x^{2}} - 7 x + 5 = 0$
Here Discriminant $= (- 7)^{2} - 4 (2) (5) = 49 - 40 = 9 > 0$
Hence the given equation has two real roots.