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:
See below, please!
Step-by-step explanation:
To multiply a whole number by a fraction, set up both numbers so that they have a numerator and denominator, multiply the corresponding parts, and simplify.
Ex: . Both of them are in fraction form, right? Now multiply the numerator and denominator together. Doing this, you get 16/6. Now simplify. Look for a common factor between both the numerator and denominator. We can see that one common factor is 2. So, our simplified fraction is 8/3.
Hope this helped!
Answer:
1. 54 and 9/20 km
2. 80 mm
3. 1.142 mi
4.0.83333 cm
Step-by-step explanation:
Do them all by the butterfly method.
Answer:
X 1 = -4,X 2 =12
EXPLANATION:
Determine the defined range
X+6/x=6/x-8,x#0,x#8
Simplify the equation using cross-multiplication
(X+6) x (x-8)=6x
Move variable to the left-hand side and change its sign
(X-6)x(x-8)-6x=0
Multiply the parentheses
X^2-8x+6x-48-6x=0
Since two opposites add up to zero, remove them from the expression
X^2-8x-48=0
Write -8x as a difference
X^2+4x-12x-48=0
Factor out x from the expression
Xx(x+4)-12x-48=0
Factor out -12 from the expression
Xx(x+4)-12(x+4)=0
Factor out from the expression
(x+4)x(x-12)=0
When the product of factors equals 0, at least one factor is 0
x+4=0
x-12=0
Solve the equation for x
X=-4
X-12=0
X=-4,x#0,x#8
Check if the solution is in the defined range
X=-4
x=12
The equation has 2 solutions
X 1 = -4,X 2 =12
Hope this helps
Answer:
The y intercept for this one is two.