A radio tower is located on a coordinate system measured in miles. The range of a signal in a particular direction is modeled by a quadratic function where the boundary of the signal starts at the vertex at [tex]\((4,2)\)[/tex] and passes through the point [tex]\((5,4)\)[/tex]. A linear road connects points [tex]\((-3,7)\)[/tex] and [tex]\((8,2)\)[/tex]. Which system of equations can be used to determine whether the road intersects the boundary of the tower's signal?

A. [tex]\(\left\{\begin{array}{r}y-2(x-4)^2=2 \\ 5 x+11 y=62\end{array}\right.\)[/tex]

B. [tex]\(\left\{\begin{aligned} y-(x-4)^2 & =2 \\ 5 x+11 y & =62\end{aligned}\right.\)[/tex]

C. [tex]\(\left\{\begin{array}{r}y-(x-4)^2=2 \\ 11 x+5 y=2\end{array}\right.\)[/tex]

D. [tex]\(\left\{\begin{array}{r}y-2(x-4)^2=2 \\ 11 x+5 y=2\end{array}\right.\)[/tex]



Answer :

Let's carefully derive the system of equations to determine whether the linear road intersects the boundary of the tower's signal.

1. Quadratic Function for Boundary of the Signal:
The quadratic function is given with the vertex at [tex]\((4, 2)\)[/tex] and passing through the point [tex]\((5, 4)\)[/tex].

The general form of a quadratic function with vertex [tex]\((h, k)\)[/tex] is:
[tex]\[ y = a(x - h)^2 + k \][/tex]
Plugging in the vertex [tex]\((4, 2)\)[/tex], this becomes:
[tex]\[ y = a(x - 4)^2 + 2 \][/tex]

We know the function passes through the point [tex]\((5, 4)\)[/tex]. Plugging in [tex]\(x = 5\)[/tex] and [tex]\(y = 4\)[/tex] into the equation:
[tex]\[ 4 = a(5 - 4)^2 + 2 \][/tex]
[tex]\[ 4 = a(1)^2 + 2 \][/tex]
[tex]\[ 4 = a + 2 \][/tex]
Solving for [tex]\(a\)[/tex], we get:
[tex]\[ a = 2 \][/tex]
Hence, the quadratic equation is:
[tex]\[ y = 2(x - 4)^2 + 2 \][/tex]
Rearranging it to standard form, we get:
[tex]\[ y - 2 = 2(x - 4)^2 \][/tex]
[tex]\[ y - 2(x - 4)^2 = 2 \][/tex]

2. Linear Equation for the Road:
The linear road passes through points [tex]\((-3, 7)\)[/tex] and [tex]\((8, 2)\)[/tex]. We can find the equation of the line by using the two-point form of the linear equation:
[tex]\[ y - y_1 = \frac{y_2 - y_1}{x_2 - x_1}(x - x_1) \][/tex]
Here, [tex]\((x_1, y_1) = (-3, 7)\)[/tex] and [tex]\((x_2, y_2) = (8, 2)\)[/tex].

The slope [tex]\(\frac{y_2 - y_1}{x_2 - x_1}\)[/tex] is:
[tex]\[ \frac{2 - 7}{8 - (-3)} = \frac{-5}{11} \][/tex]
So, the equation becomes:
[tex]\[ y - 7 = \frac{-5}{11}(x + 3) \][/tex]
Multiplying through by 11 to clear the fraction:
[tex]\[ 11(y - 7) = -5(x + 3) \][/tex]
[tex]\[ 11y - 77 = -5x - 15 \][/tex]
[tex]\[ 11y + 5x = 62 \][/tex]

Rewriting in the standard form:
[tex]\[ 5x + 11y = 62 \][/tex]

Now, we have our system of equations:

1. [tex]\(y - (x - 4)^2 = 2\)[/tex]
2. [tex]\(5x + 11y = 62\)[/tex]

Therefore, the system of equations that can be used to determine whether the road intersects the boundary of the tower's signal is:
[tex]\[ \left\{ \begin{aligned} y - (x - 4)^2 & = 2 \\ 5x + 11y & = 62 \end{aligned} \right. \][/tex]

Thus, the correct answer is:
[tex]\[ \left\{ \begin{aligned} y-(x-4)^2 & =2 \\ 5 x+11 y & =62 \end{aligned} \right. \][/tex]