Question

Identify the equation of the translated graph in general form (Picture provided)

Answer 1

Answer:

The equation after translation is x² + y² + 16x - 8y + 73 = 0 ⇒ answer (a)

Step-by-step explanation:

* Lets study the type of the equation:

∵ Ax² + Bxy + Cy² + Dx + Ey + F = 0 ⇒ general form of conic equation

- If D and E = zero

∴ The center of the graph is the origin point (0 , 0)

- If B = 0

∴ The equation is that of a circle

* Lets study our equation:

 x² + y² = 7 ⇒ x² + y² - 7 =0

∵ B = 0 , D = 0 , E = 0

∴ It is the equation of a circle with center origin

- The equation of the circle with center origin in standard form is:

  x² + y² = r²

∴ x² + y² = 7 is the equation of a circle withe center (0 , 0)

  and its radius = √7

* We have two translation one horizontally and the other vertically

- Horizontal: x-coordinate moves right (+ve value) or left (-ve value)

- Vertical: y-coordinate moves up (+ve value) down (-ve value)

∵ The point of translation is (-8 , 4)

∵ x = -8 (-ve value) , y = 4 (+ve value)

∴ The circle moves 8 units to the left and 4 units up

* now lets change the x- coordinate and the y-coordinate

  of the center (0 , 0)

∴ x-coordinate of the center will be -8

∵ y-coordinate of the center will be 4

* That means the center of the circle will be at point (-8 , 4)

- the standard form of the equation of the circle with center (h , k) is

 (x - h)² + (y - k)² = r²

∵ h = -8 and y = 4

∴ The equation is: (x - -8)² + (y - 4)² = 7

∴ (x + 8)² + (y - 4)² = 7

* lets change the equation to the general form by open the brackets

∴ x² + 16x + 64 + y² - 8y + 16 - 7 = 0

* Lets collect the like terms

∴ x² + y² + 16x - 8y + 73 = 0

∴ The equation after translation is x² + y² + 16x - 8y + 73 = 0

* Look at the graph the blue circle is after translation