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. 9
• B. -9
• C. $\pm 3$
• D. -6

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 the above figure.
The roots of the equation $y=x^2-9$ are
$x^2-9=0\Rightarrow x^2=9\Rightarrow x=\pm \sqrt{9}\Rightarrow x=\pm 3$
x = 3, -3 are the new roots of the quadratic equation.