Question

Solve the following quadratic equation by completing the square: $x^2+6x-7=0$

• A. $-7,1$
• B. $-4,1$
• C. $-7,2$
• D. None of these

Answer 1

The correct option is A $-7,1$

$\Rightarrow$ The given quadratic equation is $x^2+6x-7=0$

$\Rightarrow$ $x^2+6x=7$

$\Rightarrow$ $x^2+6x+9=7+9$ [ Adding $9$ on both sides ]

$\Rightarrow$ $(x+3{)}^2=16$

$\therefore$ $x+3=\pm 4$ [ Taking square root on both sides ]

$\Rightarrow$ $x+3=4$ and $x+3=-4$

$\therefore$ $x=1$ and $x=-7$