Questions: Enter the vertex:
Enter the x-intercept (3):
Enter the y-intercept(s):
Choose the correct graph.
Transcript text: Enter the vertex: $\square$
Enter the x-intercept (3): $\square$
Enter the y-intercept(s): $\square$
Choose the correct graph.
Solution
Solution Steps
Step 1: Find the vertex.
The given quadratic function is $f(x) = -x^2 + 2x + 5$. The x-coordinate of the vertex is given by $x = -\frac{b}{2a}$, where $a = -1$ and $b = 2$. So, $x = -\frac{2}{2(-1)} = 1$.
The y-coordinate is $f(1) = -(1)^2 + 2(1) + 5 = -1 + 2 + 5 = 6$.
Thus, the vertex is $(1, 6)$.
Step 2: Find the x-intercepts.
To find the x-intercepts, we set $f(x) = 0$ and solve for $x$.
$-x^2 + 2x + 5 = 0$
$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{-2 \pm \sqrt{2^2 - 4(-1)(5)}}{2(-1)} = \frac{-2 \pm \sqrt{4 + 20}}{-2} = \frac{-2 \pm \sqrt{24}}{-2} = \frac{-2 \pm 2\sqrt{6}}{-2} = 1 \mp \sqrt{6}$
$x \approx 1 \pm 2.45$
$x_1 \approx 1 - 2.45 = -1.45$, $x_2 \approx 1 + 2.45 = 3.45$
The x-intercepts are approximately $(-1.5, 0)$ and $(3.5, 0)$.
Step 3: Find the y-intercept.
To find the y-intercept, we set $x = 0$ in the function $f(x)$:
$f(0) = -(0)^2 + 2(0) + 5 = 5$
The y-intercept is $(0, 5)$.
Final Answer:
Vertex: $(1, 6)$
x-intercepts: $(-1.5, 0)$ and $(3.5, 0)$
y-intercept: $(0, 5)$
The correct graph is the second graph.