The number of pencils is directly proportional to the cost. ... Two values x and y are inversely proportional to each other when their product xy is a constant (always remains the same). This means that whenx increases y will decrease, and vice versa, by an amount such that xyremains the same.
Answer:
225
Step-by-step explanation:
I took the quiz I got this question wrong but the answer is 225
So you want to solve for x?
It would be nice if this would easily factor:
(-4x + 5)(2x +1) = 0 This will not work!
So you need to use the quadratic formula:
a = -8, b = 4, c = 5
![x = \frac{-b+/- \sqrt{b^{2}-4ac} }{2a}](https://tex.z-dn.net/?f=%20%20x%20%3D%20%5Cfrac%7B-b%2B%2F-%20%20%5Csqrt%7Bb%5E%7B2%7D-4ac%7D%20%7D%7B2a%7D)
x = (-4 +/-
![\sqrt{16-4(-8)(5)}](https://tex.z-dn.net/?f=%20%5Csqrt%7B16-4%28-8%29%285%29%7D%20)
)/2(-8)
= (-4 +/-
![\sqrt{16 + 160}](https://tex.z-dn.net/?f=%20%20%5Csqrt%7B16%20%2B%20160%7D%20%20)
)/-16
= (-4 +
![\sqrt{176}](https://tex.z-dn.net/?f=%20%5Csqrt%7B176%7D%20)
)/-16
= 1/4 -
![\sqrt{11}](https://tex.z-dn.net/?f=%20%5Csqrt%7B11%7D%20)
/4
I know for a fact that the Airjet Express had shorter flight times because it had lesser dots than the Cross Country Airlines. Hope this helped!