Answer:
The answer is ellipse of equation 4x² + 5y² - 40x + 60y + 260 = 0 ⇒ answer (b)
Step-by-step explanation:
* At first lets talk about the general form of the conic equation
- Ax² + Bxy + Cy² + Dx + Ey + F = 0
∵ B² - 4AC < 0 , if a conic exists, it will be either a circle or an ellipse.
∵ B² - 4AC = 0 , if a conic exists, it will be a parabola.
∵ B² - 4AC > 0 , if a conic exists, it will be a hyperbola.
* Now we will study our equation:
* 4x² + 5y² = 20
∵ A = 4 , B = 0 , C = 5
∴ B² - 4 AC = (0)² - 4(4)(5) = -80
∴ B² - 4AC < 0
∴ The graph is ellipse or circle
* If A and C are nonzero, have the same sign, and are not
equal to each other, then the graph is an ellipse.
* If A and C are equal and nonzero and have the same
sign, then the graph is a circle.
∵ A and C have same signs with different values
∴ It is an ellipse
* Now lets study T(5 , -6), that means the graph will translate
5 units to the right and 6 units down
∴ x will be (x - 5) and y will be (y - -6) = (y + 6)
* Lets substitute the x by ( x - 5) and y by (y + 6) in the equation
∴ 4(x - 5)² + 5(y + 6)² = 20
* Use the foil method
∴ 4(x² - 10x + 25) + 5(y² + 12y + 36) = 20
* Open the brackets
∴ 4x² - 40x + 100 + 5y² + 60y + 180 = 20
* Collect the like terms
∴ 4x² + 5y² - 40x + 60y + 280 = 20
∴ 4x² + 5y² - 40x + 60y + 280 - 20 = 0
∴ 4x² + 5y² - 40x + 60y + 260 = 0
* The answer is ellipse of equation 4x² + 5y² - 40x + 60y + 260 = 0
