Y=-2/5x + 4.5 , that because 4.5 is on the y coordinate and it is descending 2 units while progressing 5 to the right
(a) 4
(b) y = sqrt(9 - (9/16)x^2)
The best guess to the formula using knowledge of the general formula for an ellipse is:
x^2/16 + y^2/9 = 1
(a). An ellipse is reflectively symmetrical across both the major and minor axis. So if you can get the area of the ellipse in a quadrant, then multiplying that area by 4 would give the total area of the ellipse. So the factor of 4 is correct.
(b). The general equation for an ellipse is not suitable for a general function since it returns 2 y values for every x value. But if we restrict ourselves to just the positive value of a square root, that problem is easy to solve. So let's do so:
x^2/16 + y^2/9 = 1
x^2/16 + y^2/9 - 1 = 0
x^2/16 - 1 = - y^2/9
-(9/16)x^2 + 9 = y^2
9 - (9/16)x^2 = y^2
sqrt(9 - (9/16)x^2) = y
y = sqrt(9 - (9/16)x^2)
10x - 35 = 15x - 10
-35 = 5x -10
-25 = 5x
-5 = x
The value of x is -5.
X^2+x-30 -- find two numbers that add to one and multiply to -30, which would be 6 and -5. so now you have x^2+6x-5x-30. factor out x and 5 to get x(x+6)-5(x+6). so you get (x+6)*(x-5)
