Check the picture below.
now, let's keep in mind that, the vertex is half-way between the focus point and the directrix, it's a "p" distance from each other.
since this horizontal parabola is opening to the left-hand-side, "p" is negative, notice in the picture, "p" is 2 units, and since it's negative, p = -2.
its vertex is half-way between those two guys, so that puts the vertex at (-5, 3)
![\bf \textit{parabola vertex form with focus point distance} \\\\ \begin{array}{llll} 4p(x- h)=(y- k)^2 \\\\ 4p(y- k)=(x- h)^2 \end{array} \qquad \begin{array}{llll} vertex\ ( h, k)\\\\ p=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix} \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \begin{cases} h=-5\\ k=7\\ p=-2 \end{cases}\implies 4(-2)[x-(-5)]=[y-7]^2 \\\\\\ -8(x+5)=(y-7)^2\implies x+5=\cfrac{(y-7)^2}{-8}\implies \boxed{x=-\cfrac{1}{8}(y-7)^2-5}](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bparabola%20vertex%20form%20with%20focus%20point%20distance%7D%20%5C%5C%5C%5C%20%5Cbegin%7Barray%7D%7Bllll%7D%204p%28x-%20h%29%3D%28y-%20k%29%5E2%20%5C%5C%5C%5C%204p%28y-%20k%29%3D%28x-%20h%29%5E2%20%5Cend%7Barray%7D%20%5Cqquad%20%5Cbegin%7Barray%7D%7Bllll%7D%20vertex%5C%20%28%20h%2C%20k%29%5C%5C%5C%5C%20p%3D%5Ctextit%7Bdistance%20from%20vertex%20to%20%7D%5C%5C%20%5Cqquad%20%5Ctextit%7B%20focus%20or%20directrix%7D%20%5Cend%7Barray%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20%5Crule%7B34em%7D%7B0.25pt%7D%5C%5C%5C%5C%20%5Cbegin%7Bcases%7D%20h%3D-5%5C%5C%20k%3D7%5C%5C%20p%3D-2%20%5Cend%7Bcases%7D%5Cimplies%204%28-2%29%5Bx-%28-5%29%5D%3D%5By-7%5D%5E2%20%5C%5C%5C%5C%5C%5C%20-8%28x%2B5%29%3D%28y-7%29%5E2%5Cimplies%20x%2B5%3D%5Ccfrac%7B%28y-7%29%5E2%7D%7B-8%7D%5Cimplies%20%5Cboxed%7Bx%3D-%5Ccfrac%7B1%7D%7B8%7D%28y-7%29%5E2-5%7D)
Answer:
-4
Step-by-step explanation:
i just took this
Let
x = the number of tapers (each coss $1)
y = the number of pillars (each costs $4)
z = the number of jars (each costs $6)
There are 8 candles in each basket, therefore
x + y + z = 8 (1)
The cost per basket is $24, therefore
x + 4y + 6z = 24 (2)
The number of tapers equals the sum of pillars and jars, therefore
x = y + z (3)
Substitute (3) into (1) and into (2).
y + z + y + z = 8
2y + 2z = 8
y + z = 4 (4)
y + z + 4y + 6z = 24
5y + 7z = 24 (5)
From (4), y = 4 -z. Substitute into (5).
5(4 - z) + 7z = 24
2z + 20 = 24
2z = 4
z = 2
y = 4 - z = 4 - 2 = 2
x = y + z = 2 + 2 = 4
Answer: 4 tapers, 2 pillars, 2 jars.
3(4)^2 -4(-5) + (4)(2)
= 3(16) + 20 + 8
= 48 + 20 + 8
= 76 (d)
Hi,
Solving:
Answer: The inequality is true for any value of x, except when X = -4
Hope this helps.
r3t40
