The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Learn more about arithmetic sequence here:
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Answer:
y+11=-2/3(x-6)
Step-by-step explanation:
To find the parallel line, we would just plug in the numbers in the point-slope form from what we're given. We have y=-2/3x+12 and (6,-11).
Point-slope form:
y-y1=m(x-x1) → y+11=-2/3(x-6)
m represents the slope, which is -2/3 in this situation.
y1 represents the y coordinate, which is -11 in this situation. However, when we plug in negative numbers in a point-slope form, we would do the opposite of the negative number, which is to make it a positive in point-slope form.
x1 represents the x coordinate, which is 6 in this situation.
Answer:
2688x^2 + 3640x + 1225
Step-by-step explanation:
multiply the expression
Answer:
The answer is 1.
Step-by-step explanation:
