Answer:
y = -4x +2
Step-by-step explanation:
As x-values increase by 1, y-values decrease by 4. The slope of the line is ...
... m = (change in y)/(change in x) = -4/1 = -4
We can use the first (x, y) pair as a point to use in the point-slope form of the equation of a line. That form can be written, for slope m and point (h, k) ...
... y = m(x -h) +k
using m = -4 and (h, k) = (1, -2), we can fill in the numbers to get ...
... y = -4(x -1) -2
... y = -4x +4 -2 . . . . eliminate parentheses
... y = -4x +2 . . . . . . slope-intercept form
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<em>Alternate approach</em>
After you recognize that a change in x of 1 gives a change in y of -4, you can work backward one step to find the table value for y corresponding to x=0. That will be -2+4 = +2. Now, you know both the slope (-4) and the y-intercept (+2), so you can write the equation directly from this knowledge:
... y = -4x +2
Answer:
n = -7,6
Step-by-step explanation:
n(n+1)+3=45
distributive property: a(b+c) = ab+ac
n²+n+3 = 45
n²+n -42 = 0
factor now
(n+7)(n-6) = 0
n = -7,6
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:
7 5/6
Step-by-step explanation:
1 1/2= 1 3/6
6 1/3= 6 2/6
1 3/6
+6 2/6
————-
7 5/6
