How do I solve these problems?
2 answers:
Answer:
-32, -7, 18 and
127, 106, 85
Step-by-step explanation:
You can use the following formula to solve this:
a is the nth term in the sequence. So at the 3rd term, n = 3
a₁ is the first term in the sequence. In your first question, a₁ is -32. In your second, a₁ is 127.
(n - 1) represents the term before a, or the term before the current term. So at the 3rd term, (n - 1) = 3-1, which is 2.
d represents the common difference between terms. Aka what you add or subtract to a term to get the next one.
For the first question, you know a₁ and d, so you can substitute them into the equation to find the second and third terms:
a = -32 + (n - 1)25
You also know (n-1), because a is 2 when you're looking for the second term. So (n-1) = 2-1, which is 1. So put that in the formula and simplify:
a = -32 + (1)25
a = -32 + 25
a = -7
The second term is -7. To find the 3rd term, do the same thing.
a = -32 + (n - 1)25
(n-1) is 2, since you're on the third term and n is 3.
a = -32 + (2)25
a = -32 + 50
a = 18
So the first 3 terms are -32, -7, and 18.
For the second one, the formula looks like this:
a = 127 + (n - 1)-21
The first term is 127. Find the 2nd (n is 2):
a = 127 + (1)-21
a = 127 -21
a = 106
Then find the 3rd term (n is 3)
a = 127 + (2)-21
a = 127 -42
a = 85
So the first 3 terms are 127, 106, and 85.
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