Let 
denote the <em>k</em>th term of the sequence. Then
where <em>d</em> is the common difference between consecutive terms in the sequence and <em>a</em>₁ is the first term.
The sum of the first <em>n</em> terms is
From the formula for , we get
So we have 
, and 
so that 
.
Then the <em>n</em>th term in the sequence is
Answer:
x=50
Step-by-step explanation:
Step-by-step explanation:
I don't understand the question
Answer:
E. -8, -29
Step-by-step explanation:
a-b=21
5a -2b =18
Take the first equation and solve for a by adding b to each side
a-b=21
a-b+b=21+b
a = 21+b
Now substitute a=21+b into the second equation
5a -2b =18
5(21+b) -2b =18
Distribute the 5
105 +5b-2b =18
Combine like terms
105 +3b =18
Subtract 105 from each side
105-105 +3b = 18-105
3b = -87
Divide each side by 3
3b/3 =-87/3
b = -29
if b = -29, we can substitute it into a =21+b
a = 21-29
a = -8
