find the first term of an AP if its 4 term is 14 and 12 term is 70
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Hii !!
4th term = 14
a + 3d = 14 ---------(1)
And,
12th term = 70
a + 11d = 70 --------(2)
From equation (1) , we get
a + 3d = 14
a = 14 - 3d -----------(3)
Putting the value of a in equation (2) , we get
a + 11d = 70
( 14 - 3d ) + 11d = 70
8d = 70 - 14
8d = 56.
D = 7
Common difference ( d ) = 7.
Putting the value of d in equation (3) , we get
a = 14 - 3d = 14 - 3×7 = 14 - 21
a = -7
4th term = 14
a + 3d = 14 ---------(1)
And,
12th term = 70
a + 11d = 70 --------(2)
From equation (1) , we get
a + 3d = 14
a = 14 - 3d -----------(3)
Putting the value of a in equation (2) , we get
a + 11d = 70
( 14 - 3d ) + 11d = 70
8d = 70 - 14
8d = 56.
D = 7
Common difference ( d ) = 7.
Putting the value of d in equation (3) , we get
a = 14 - 3d = 14 - 3×7 = 14 - 21
a = -7
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