Answer:
Step-by-step explanation:
a. 4x+4y
b. 8a+24b
c. 6x+33y
d. 63a+54b
e. 3ac+bc
f. 2xy+11yz
Answer:
The population will reach 34,200 in February of 2146.
Step-by-step explanation:
Population in t years after 2012 is given by:
![P(t) = 0.8t^{2} + 6t + 19000](https://tex.z-dn.net/?f=P%28t%29%20%3D%200.8t%5E%7B2%7D%20%2B%206t%20%2B%2019000)
In what month and year will the population reach 34,200?
We have to find t for which P(t) = 34200. So
![P(t) = 0.8t^{2} + 6t + 19000](https://tex.z-dn.net/?f=P%28t%29%20%3D%200.8t%5E%7B2%7D%20%2B%206t%20%2B%2019000)
![0.8t^{2} + 6t + 19000 = 34200](https://tex.z-dn.net/?f=0.8t%5E%7B2%7D%20%2B%206t%20%2B%2019000%20%3D%2034200)
![0.8t^{2} + 6t - 15200 = 0](https://tex.z-dn.net/?f=0.8t%5E%7B2%7D%20%2B%206t%20-%2015200%20%3D%200)
Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots
such that
, given by the following formulas:
![x_{1} = \frac{-b + \sqrt{\bigtriangleup}}{2*a}](https://tex.z-dn.net/?f=x_%7B1%7D%20%3D%20%5Cfrac%7B-b%20%2B%20%5Csqrt%7B%5Cbigtriangleup%7D%7D%7B2%2Aa%7D)
![x_{2} = \frac{-b - \sqrt{\bigtriangleup}}{2*a}](https://tex.z-dn.net/?f=x_%7B2%7D%20%3D%20%5Cfrac%7B-b%20-%20%5Csqrt%7B%5Cbigtriangleup%7D%7D%7B2%2Aa%7D)
![\bigtriangleup = b^{2} - 4ac](https://tex.z-dn.net/?f=%5Cbigtriangleup%20%3D%20b%5E%7B2%7D%20-%204ac)
In this question:
![0.8t^{2} + 6t - 15200 = 0](https://tex.z-dn.net/?f=0.8t%5E%7B2%7D%20%2B%206t%20-%2015200%20%3D%200)
So ![a = 0.8, b = 6, c = -15200](https://tex.z-dn.net/?f=a%20%3D%200.8%2C%20b%20%3D%206%2C%20c%20%3D%20-15200)
Then
![\bigtriangleup = 6^{2} - 4*0.8*(-15100) = 48356](https://tex.z-dn.net/?f=%5Cbigtriangleup%20%3D%206%5E%7B2%7D%20-%204%2A0.8%2A%28-15100%29%20%3D%2048356)
![t_{1} = \frac{-6 + \sqrt{48356}}{2*0.8} = 134.14](https://tex.z-dn.net/?f=t_%7B1%7D%20%3D%20%5Cfrac%7B-6%20%2B%20%5Csqrt%7B48356%7D%7D%7B2%2A0.8%7D%20%3D%20134.14)
![t_{2} = \frac{-6 - \sqrt{48356}}{2*0.8} = -141.64](https://tex.z-dn.net/?f=t_%7B2%7D%20%3D%20%5Cfrac%7B-6%20-%20%5Csqrt%7B48356%7D%7D%7B2%2A0.8%7D%20%3D%20-141.64)
We only take the positive value.
134 years after 2012.
.14 of an year is 0.14*365 = 51.1. The 51st day of a year happens in February.
So the population will reach 34,200 in February of 2146.
Answer:
i think it is B hope it help
Step-by-step explanation:
No, because if he runs 7/30 mile each day he will run 210 miles each week because he is running 30 miles every day so he has to run 7/4.28 miles each day of the week to get 30 miles each week.