The 9th term of an ap is ewual to 7times the 2nd and the 12th term exceeds the 5times the 3rd term by 2 find a and d
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Step-by-step explanation:
the conditon
T₉ = 7 X T₂
a + 8d = 7 x (a +d)
a +8d = 7a + 7d
6a = d
so d = 6a................(2)
now the second condition is:
T₁₂ = 5 x T3 + 2
a + 11d = 5(a+2d)+2
a + 11d = 5a + 10d +2
a + 66a = 5a +2
67a - 5a =2
62a =2
a = 2/62
now sub in (2)
b = 12/62
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