Find the zeros of the quadratic function by completing the square. List the x-intercepts of the graph of the function.
-$$F ( x ) = x ^ { 2 } + 6 x - 40$$
A) $x = \sqrt { - 40 } , x = \sqrt { 40 }$
B) $x = - 30 , x = - 10$
C) $x = - 4 , x = 10$
D) $x = 4 , x = - 10$

Question

Quizplus · Accepted Answer

To find the zeros by completing the square, rewrite the function as $F(x) = (x + 3)^2 - 49$. Setting $F(x) = 0$, we get $(x + 3)^2 = 49$, leading to $x + 3 = \pm 7$. Solving gives $x = 4$ and $x = -10$.

Find the Zeros of the Quadratic Function by Completing the Square