d = 3 , a₁₂ = 40 and S
= 7775
In an arithmetic sequence the nth term and sum to n terms are
<h3>• a
= a₁ + (n-1)d</h3><h3>• S
=
[2a + (n-1)d]</h3><h3>
where d is the common difference</h3><h3>a₆ = a₁ + 5d = 22 ⇒ 7 + 5d = 22 ⇒ 5d = 15 ⇔ d = 3</h3><h3>a₁₂ = 7 + 11d = 7 +( 11× 3) = 7 + 33 = 40</h3><h3>S₁₀₀ =
[(2×7) +(99×3)</h3><h3> = 25(14 + 297) = 25(311)= 7775</h3>
To figure this out, we need to use fractional proportions.
Currently, we have $120, the amount earned, and 2 days, the current rate.
Our fraction for this is: 120 / 2 = x / 6, x being the amount earned in 6 days.
Let's use a little technique to help us answer faster.
With our current money earned, 120, and our current days, 2, we can divide 120 by 2 to find out how many we earned in 1 day.
120 / 2 = 60.
We earned $60 per day.
With this formula, 60d, d being the amount of days, we can solve quicker.
We are solving for 6 days, so multiply $60 by 6 days.
60 x 6 = 360
Your proportion is :
120/2 : 360/6
I hope this helps!
First, order the number set from least to greatest:
3 , 4 , 4 , 7 , 8 , 9 , 12 , 14 , 16 , 20
Mean: You find the mean by combining all the terms, and dividing by the amount of the terms there are in the number set:
(3 + 4 + 4 + 7 + 8 + 9 + 12 + 14 + 16 + 20)/10
(97)/10 = 9.7
Mean: 9.7
Median: You find the median by first ordering the number set from least to greatest, and finding the middle number. Note that if there is a even number of numbers in the set, you find the mean with the two given median digits:
8 & 9 are the median numbers:
(8 + 9)/2 = (17)/2 = 8.5
Median: 8.5
Mode: The mode is the number(s) in the set that shows up the most:
Mode: 4 (shows up one more time than all other numbers)
Range: The range can be found by subtracting the least number from the greatest number in the number set:
Range: 20 - 3 = 17
Range: 17
~
(3x² -7x⁴) from (5x² - 3x⁸)
= 5x² - 3x⁸ - (3x² -7x<span>⁴ )
= </span> 5x² - 3x⁸ - 3x² + 7x<span>⁴
= </span>- 3x⁸ + 7x⁴ + 5x² <span>- </span><span>3x²
</span>
= - 3x<span>⁸ </span>+ 7x⁴ + 2x<span>²</span>
