Answer:
11
Step-by-step explanation:
5 1/2 x 2= 11
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:
x is greater than -5
Step-by-step explanation:
47.60514678
What I did was 28 squared plus b squared equals 38.25 squared and ya......
Answer:
x = -2 and y = 2
Step-by-step explanation:
The given equations are :
-5x-2y=6 ...(1)
3x+6y=6 ...(2)
Multiply equation (1) by 3. SO,
-15x-6y=18 ...(3)
Adding equation (2) and (3).
3x+6y-15x-6y = 6+18
-12x = 24
x = -2
Put the value of x in equation (1).
-5(-2)-2y=6
10-2y=6
4=2y
y = 2
So, the value of x is -2 and y is 2.
