Question

Form a quadratic equation whose roots are:
$3,4$

• A. $x^2-7x+12=0$
• B. $x^2+7x+12=0$
• C. $x^2-7x-12=0$
• D. None of these

Answer 1

Answer: (A)

$x^2-7x+12=0$

$\Rightarrow$ The given roots are $3,4$

$\Rightarrow$ Sum of the roots $=3+4=7$ ----- ( 1 )

$\Rightarrow$ Product of the roots $=3\times 4=12$ ----- ( 2 )

$\Rightarrow$ We know, $x^2-\left(sumoftheroots\right)x+\left(Productoftheroots\right)=0$

From ( 1 ) and ( 2 ),

$\Rightarrow$ $x^2-7x+12=0$