Two students while solving a quadratic equation in x, one copied … - Vidyadip

MCQ

Two students while solving a quadratic equation in $x$, one copied the constant term incorrectly and got the roots $3$ and $2$. The other copied the constant term and coefficient of ${x^2}$ correctly as $-6$ and $1$ respectively. The correct roots are

A
$3, -2$
B
$ - 3,\,2$
C
$-6, -1$
✓
$6, - 1$

✓

Answer

Correct option: D.

$6, - 1$

d
(d) Let the correct equation be $a{x^2} + bx + c = 0$ and the correct roots $\alpha $ and$\beta $.

Taking $c$ wrong, the roots are $3$ and $2$.

? $\alpha + \beta = 3 + 2 = 5$ .....$(i)$

Also $a = 1$ and $c = - 6$

? $\alpha \beta = c/a = - 6$.....$(ii)$

Solving $(i)$ and $(ii)$, the correct roots are $6$ and $-1$.

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