If your directrix is a "y=" line, that means that the parabola opens either upwards or downwards (as opposed to the left or the right). Because it is in the character of a parabola to "hug" the focus, our parabola opens upwards. The vertex of a parabola sits exactly halfway between the directrix and the focus. Since our directrix is at y = -2 and the focus is at (1, 6) AND the parabola opens upward, the vertex is going to sit on the main transversal, which is also the "line" the focus sits on. The focus is on the line x = 1, so the vertex will also have that x coordinate. Halfway between the y points of the directrix and the focus, -2 and 6, respectively, is the y value of 2. So the vertex sits at (1, 2). The formula for this type of parabola is
where h and k are the coordinates of the vertex and p is the DISTANCE that the focus is from the vertex. Our focus is 4 units from the vertex, so p = 4. Filling in our h, k, and p:
. Simplifying a bit gives us
. We can begin to isolate the y by dividing both sides by 16 to get
. Then we can add 2 to both sides to get the final equation
, choice 4 from above.
Answer:
y+4 = 9/4(x-3)
Step-by-step explanation:
The point slope form of an equation is
y-y1 = m(x-x1) where m is the slope and (x1,y1) is the point
Substituting in what we know
y--4 = 9/4(x-3)
y+4 = 9/4(x-3)
Answer: the answer is b
Step-by-step explanation:
Given two points, the equation of the line may be determined by,
y - y1 = ((y2 - y1) / (x2 - x1))(x - x1)
Substituting the given values,
y - 7 = ((9 - 7) / (6 - 3))(x - 3)
Simplification will yield to an answer of,
y = 2x/3 +5
Thus, the answer is the second choice.
hope this helps :)
Answer:If I’m correct I believe seven you cars for 16.45 would be better
Step-by-step explanation:
Since three cars cost 7.50 you would divide 7.50 to get the cost for each car which would give you 2.50 and since seven cars cost 16.45 you would divide 16.45 by 7 to get the cost of each car which would come out to 2.35 making it a better buy
The point value is irrelevant. 18/24 as a decimal is 0.75, so your grade was 0.75, or 75%
Your grade is 75% in percentage form.