The Second Term Of Arithmetic Sequence Is 24 And The Fifth Term Is 3.Find The First Term And The Common Difference ...Please Show Me Your Solution
The second term of arithmetic sequence is 24 and the fifth term is 3.Find the first term and the common difference ...please show me your solution
Answer:
First term (a₁) = 31
Common difference (d) = -7
Step-by-step explanation:
Arithmetic sequence general nth rule:
an = a₁ + (n-1)(d)
Where:
an = last term
n = the number of terms in a sequence or the nth term
a₁ = first term
d = common difference
Given:
a₂ = 24; n=2
24 = a₁ + (2-1)(d)
24 = a₁ + d
a₁ = 24-d
a₅ = 3; n = 5
3 = a₁ + (5-1)(d)
a1 = 3 - 4d
Find d, the common difference by equating 24-d and 3-4d:
24 - d = 3 - 4d
4d - d = 3 - 24
3d/d = -21/3
d = -7
Find the first term, a₁:
a₁ = 3-4d
a₁ = 3 - 4(-7)
a₁ = 3 + 28
a₁ = 31
OR
a₁ = 24 - d
a₁ = 24 - (-7)
a₁ = 24 +7
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