Sum of first n terms of an ap sequance is 3n2+5n.what is the sum of its first n+1 terms.find the sum of its first 10 terms.
1 answer:
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Answer:
x = -14
Step-by-step explanation:
The expression to write in this problem is:
"the sum of x and 12 equals the sum of half of x and 5"
We have:
- The sum of x and 12 is:
- The sum of half of x and 5 is:
So, the equation to write in this problem is
We solve it as follows:
1) First, we subtract from both sides, and we get
2) Then, we subtract 12 from both sides:
3) Now we multiply both sides by 2:
So, this is the solution.