Choose the correct answer from the given four options in the following questions:
Which of the following equations has 2 as a root?
(A) $ x^{2}-4 x+5=0 $
(B) $ x^{2}+3 x-12=0 $
(C) $ 2 x^{2}-7 x+6=0 $
,b>(D) $ 3 x^{2}-6 x-2=0 $

AcademicMathematicsNCERTClass 10

To do:

We have to find the correct answer.

Solution:

Substituting $x=2$ in $x^{2}-4 x+5$, we get,

$(2)^{2}-4(2)+5=4-8+5$

$=1 ≠ 0$

So, $x=2$ is not a root of $x^{2}-4 x+5=0$.

Substituting $x=2$ in $x^{2}+3 x-12$, we get,

$(2)^{2}+3(2)-12=4+6-12$

$=-2 ≠ 0$

So, $x=2$ is not a root of $x^{2}+3 x-12=0$.

Substituting $x=2$ in $2 x^{2}-7 x+6$, we get,

$2(2)^{2}-7(2)+6 =2(4)-14+6$

$=8-14+6$

$=14-14$

$=0$

So, $x=2$ is a root of the equation $2 x^{2}-7 x+6=0$.

Substituting $x=2$ in $3 x^{2}-6 x-2$, we get,

$3(2)^{2}-6(2)-2=12-12-2$

$=-2 ≠ 0$

So, $x=2$ is not a root of $3 x^{2}-6 x-2=0$.

raja
Updated on 10-Oct-2022 13:27:26

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