Given that the directrix is at y = 4 and the focus is at (0, -4), then the vertex is at (h, k) = (0, 0).
p is the distance between the vertex and the focus and between the vertex and the directrix = 4 and since the focus is below the directrix, p is negative, i.e. p = -4
Equation of a parabola is given by (x - h)^2 = 4p(y - k)
Therefore, the required equation is (x - 0)^2 = 4(-4)(y - 0)
x^2 = -16y
y = -1/16 x^2
The equation of the area of a triangle is Area=Length×Width. We know area=256.5 and length is 18. So now we know 256.5=18×width. We then divide 256.5÷18 to get the width. The width is 14.25. Perimeter=legth+length+width+width. If width is 18 and length is 14.25 then we add up all 4 sides. 18+18+14.25+14.25=64.5. 64.5 is the perimeter
A 120 watt light-bulb is a 0.120 kilowatt light bulb.
In one hour, it uses 0.120 kilowatt-hour of energy.
If electrical energy costs $0.20 per kilowatt hour, then that light bulb costs
(0.120 kilowatt-hour / hour) x (0.20 dollar / kilowatt-hour) =
(0.120 x $0.20 / hour) =
$0.024 / hour = <span>2.4¢ per hour </span>
Answer: 5p - 4
5 times ‘p’ = 5p
4 less than ‘p’ = p - 4
Therefore,
=> 5p - 4
