Math, asked by abhinandnavaneetham, 1 month ago

The 5th term of an Arithmetic sequence is 20 and the 8th term is 32 What is the first term of this sequence ?​

Answers

Answered by suhail2070
1

Answer:

FIRST TERM IS 4.

Step-by-step explanation:

a + 4d = 20 \\  \\  \\ a + 7d = 32 \\  \\  \\ solving \: these \\  \\  \\ 3d = 12 \\  \\ d = 4 \\  \\ then \:  \:  \:  \: a + 4(4) = 20 \\  \\ a = 20 - 16 \\  \\ a = 4 \\  \\  \\

Answered by linanguyenyt
0

Answer:

4

Step-by-step explanation:

TO KNOW :- aₙ= a + (n - 1) d

Here ,

a{n} → 'n'th term.

a → 1st term.

n → Number of terms.

d → Common difference.

SOLUTION :-

♦ 5th term of A.P is 20.

We have ,

n = 5

a{5} = 20

Putting values ,

20 = a + (5 - 1)d

20 = a + 4d --------(1)

Also,

♦ 8th term is 32.

We have,

a{n} = 32

n = 8

Putting values ,

→ 32 = a + (8-1)d

→ 32 = a + 7d ---------(2)

Subtracting equation (2) by equation (1) ,

→ 20 - 32 = a + 4d - (a + 7d)

→ -12 = a + 4d - a - 7d

→ -12 = -3d

→ d = -12/-3

→ d = 4

Hence , Common difference is 4.

Putting d = 4 in equation (1) ,

→ 20 = a + 4d

→ 20 = a + 4(4)

→ 20 = a + 16

→ a = 20 - 16

→ a = 4

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