Answer:

Step-by-step explanation:
The terms of this sum make the arithmetic sequence.
The fomula of a sum of <em>n</em> terms of an arithmetic sequence:
![S_n=\dfrac{[2a_1+(n-1)d]\cdot n}{2}](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7B%5B2a_1%2B%28n-1%29d%5D%5Ccdot%20n%7D%7B2%7D)
We have

Substitute:
![S_{50}=\dfrac{[2\cdot2+(50-1)\cdot15]\cdot50}{2}=(4+49\cdot15)\cdot25=(4+735)\cdot25\\\\=739\cdot25=18,475](https://tex.z-dn.net/?f=S_%7B50%7D%3D%5Cdfrac%7B%5B2%5Ccdot2%2B%2850-1%29%5Ccdot15%5D%5Ccdot50%7D%7B2%7D%3D%284%2B49%5Ccdot15%29%5Ccdot25%3D%284%2B735%29%5Ccdot25%5C%5C%5C%5C%3D739%5Ccdot25%3D18%2C475)
Answer:
3/10 and 4/10 4/12 and 9/12
Step-by-step explanation:
Answer:
About 5043.58
Step-by-step explanation:
The standard form for an exponential decay after t time is:

Where a is the initial value, r is the rate decay, t is the time that has passed, and d is the amount of time it takes for 1 cycle.
The initial value is 9800. So a = 9800.
The quantity cuts in half. So, r = 1/2.
And it cuts in half every 6 days. For this question, we will convert this to hours. 6 days = 144 hours. So, we can let d = 144, where t will be in hours.
Therefore, our function is:

Where t is the amount of time that has passed, in hours.
Then the quantity left after 138 hours will be:

Answer:
Step-by-step explanation:
Solving
5x + -2y = 12
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '2y' to each side of the equation.
5x + -2y + 2y = 12 + 2y
Combine like terms: -2y + 2y = 0
5x + 0 = 12 + 2y
5x = 12 + 2y
Divide each side by '5'.
x = 2.4 + 0.4y
Simplifying
x = 2.4 + 0.4y
d1 = ax + by + c = 0 and d2= mx + ky + f = 0
if they are parallel :

8x + 2y = 7
8x + 2y - 7 = 0
- 8x + 2y -9 = 0
- 4x + y -6 = 0
- 16x + 4y - 19 = 0
you can create more whatever you want =)
Hope this helps ^-^