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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 $
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 $3 x^{2}-6 x-2=0$.
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