Question

The figure shows the graph of $y=x^2$. This graph is shifted downward by 9 units. Find the new roots of the equation.

• A. $\pm 9$
• B. $\pm 6$
• C. $\pm 3$
• D. None of these

Answer 1

The correct option is C

$\pm 3$

The graph of $y=x^2$ when shifted by 9 units down becomes $y=x^2-9$ as shown in figure.
The roots of the equation $y=x^2-9$ are
$x^2-9=0\Rightarrow (x-3)(x+3)=0\Rightarrow x=\pm 3$
So, $x=3,-3$ are the new roots of the quadratic equation.