What is the sum of the arithmetic sequence 3, 9, 15..., if there are 36 terms?
2 answers:
We know that
the formula of the <span>the sum of the arithmetic sequence is
Sum=n*(a1+an)/2
n=36
a1=3
a36=?
find a36
an=a1+(n-1)*d
for n=2 a2=9
9=3+(2-1)*d----> 9=3+d----> d=6
so
for n=36
a36=a1+(36-1)*6----> a36=3+35*6----> a36=213
</span>Sum=n*(a1+an)/2-----> 36*[3+213]/2----> 3888
the answer is
3888
Answer:B✓
Step-by-step explanation:
The answer is 3,888
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Answer:
The answer is x=-6
Step-by-step explanation:
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Your answer is x = 3.
-3(x + 5) = 6 - 3(2x + 4)
-3x - 15 = 6 -6x - 12
-3x - 15 = -6 - 6x
-3x + 6x = -6 + 15
3x = -6 + 15
3x = 9
x = 3