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प्रश्न
For an given A.P., t7 = 4, d = −4, then a = ______.
विकल्प
6
7
20
28
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उत्तर
For an given A.P., t7 = 4, d = −4, then a = 28.
Explanation:
Given,
t7 = 4
d = −4
Now,
tn = a + (n − 1)d
t7 = a + (7 − 1)d
⇒ 4 = a + 6(−4)
⇒ 4 = a − 24
⇒ a = 4 + 24
⇒ a = 28
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