I am doing a test please help

Which equation represents the equation of the parabola with focus (-3 3) and directrix y=7?

Artemon [7]

Answer:

The equation $y=\frac{-x^2-6x+31}{8}$ represents the equation of the parabola with focus (-3, 3) and directrix y = 7.

Step-by-step explanation:

To find the equation of the parabola with focus (-3, 3) and directrix y = 7. We start by assuming a general point on the parabola (x, y).

Using the distance formula $d = \sqrt {\left( {x_1 - x_2 } \right)^2 + \left( {y_1 - y_2 } \right)^2 }$ , we find that the distance between (x, y) is

$\sqrt{(x+3)^2+(y-3)^2}$

and the distance between (x, y) and the directrix y = 7 is

$\sqrt{(y-7)^2}$ .

On the parabola, these distances are equal so, we solve for y:

$\sqrt{(x+3)^2+(y-3)^2}=\sqrt{(y-7)^2}\\\\\left(\sqrt{\left(x+3\right)^2+\left(y-3\right)^2}\right)^2=\left(\sqrt{\left(y-7\right)^2}\right)^2\\\\x^2+6x+y^2+18-6y=\left(y-7\right)^2\\\\x^2+6x+y^2+18-6y=y^2-14y+49\\\\y=\frac{-x^2-6x+31}{8}$

6 0

3 years ago

Tickets to a hockey game cost $35 each. What is the total cost for 5 tickets?

nordsb [41]

The answer would be $175

Multiply the most by the number of tickets

5 0

2 years ago

Read 2 more answers

Find the area A of triangle JKL with the vertices J(5,8), K(0,7), and L(5,4)

eimsori [14]

Answer:

Area of the triangle is 10 square units

Step-by-step explanation:

Recall that the formula for the area of a triangle is: "base x height / 2", and in this case, we can consider the triangle's base as the segment that joins the vertices (5, 4) and (5, 8) which gives a segment length of 4 units. The height of the triangle is then the distance between the third vertex (0,7) and the base, which is exactly 5 units. Then the area becomes:

Area = 4 x 5 / 2 = 10 square units.

5 0

3 years ago

The table represents quadratic function g. Which statement is true about the function?

weqwewe [10]

Answer:

B. The maximum occurs at the function's x-intercept.

Step-by-step explanation:

Given table:

$\large\begin{array}{| c | c | c | c | c | c | c |}\cline{1-7} x & -5 & -4 & -3 & -2 & -1 & 0\\\cline{1-7} g(x) & -1 & 0 & -1 & -4 & -9 & -16\\\cline{1-7}\end{array}$

From inspection of the table, we can see that:

$g(-5) = -1$ and
$g(-3) = -1$

This indicates symmetry.

The line of symmetry is the mid-point between the two x-values.

Therefore, the line of symmetry is x = -4

The vertex (minima/maxima) is on the line of symmetry, therefore the vertex is at (-4, 0). As the function decreases as x → 0, the vertex is a maximum.

As the y-value of the vertex is 0, the maximum occurs at the function's x-intercept.

3 0

2 years ago

Read 2 more answers

Simon must maintain an average grade of 80% or better in his math class to be eligible to play sports.His math grade so far are

Sophie [7]

Answer:

Let x be the percentage score he got in fifth test,

According to the question,

His score in first, second, third and fourth test are 80%, 84%, 76% and 77% respectively,

Thus, the average of his total score in the five test,

= $\frac{80+84+76+77+x}{5}$