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
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Answer:
kkk
Step-by-step explanation:
Step 1: Write out the problem.
Step 1: Write out the problem.
Step 1: Write out the problem.
x+(x+1)+(x+2)+(x+3)= 286
Step 2: Take out the parentheses.
x+x+1+x+2+x+3= 286
Step 3: Combine like terms.
4x+6= 286
Step 4: Subtract 6 from both sides.
4x+6 -6= 286 -6
Step 5: Divide 4 on both sides.
4x/4 = 280/4
x=70
Which means the answer is 70, 71, 72, 73
Check Work:
70+71+72+73= 286
So this is correct :)
= 2ab + 4a + 6 - 6
= 2ab + 4a
you can factor this to 2a(b + 2)
The answer is B, C, and D. Like terms are terms with all the same variable, so 5x and -x are like terms.
C is correct. If we add -x to 5x, we get 4x. The other numbers remain unchanged because they have no like terms.
D is correct. Applying the rule of like terms, which is that like terms are numbers with the same variable, only add together numbers with the same variable.
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