Question

for an AP . if
P4=20 and
t7=32 find
a,d an tn term?​

Answer 1

Answer:

Step-by-step explanation:

nth tern of AP is given by tₙ = a + (n - 1)d

t₄ = a + (4 - 1)d = 20

    => a + 3d = 20  ------------- (1)

t₇ = a + (7 - 1)d = 32

    => a + 6d = 32  ------------- (2)

Subtract (1) from (2)

a + 6d = 32

a + 3d = 20

-  -         -

--------------------

3d = 12

=> d = 4

Substitute value of d in any of the equations (1) or (2)

substituting in (1), a + 12 = 20 => a = 8.

nth term of AP = 8 + (n - 1)4 = 4n + 4

So a = 8, d = 4 and tₙ = 4n + 4

Answer 2

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a = 8

d = 4

t_n = 4n + 4