three terms are there in Ap whose sum is 21 and their product is 231 find the term
plzz solve it's imp for my exam
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three terms are there in Ap whose sum is 21 and their product is 231 find the term
plzz solve it's imp for my exam
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[Always remember this]
To find 3 terms in an AP
take these terms---- (a-d), a, (a+d)
to find 4 terms----- (a-3d), (a-d), (a+d), (a+3d)
to find 5 terms----- (a-2d), (a-d), a, (a+d), (a+2d)
to find 6 terms----- (a-5d), (a-3d), (a-d), (a+d), (a+3d), (a+5d)
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NOW, LET'S SOLVE YOUR QUESTION
let the three terms are :-
(a-d), a, (a+d)
case 1 :-
sum of these terms = 21
(a - d) + (a) + (a+d) = 21
a - d + a + a + d = 21
d cancels out
3a = 21
a = 7
Case 2 :-
product of these terms = 231
(a-d)*a*(a+d) = 231
put the value of a
Now, we got both 'a' and 'd'
(a-d) = 7-4 = 3
a = 7
(a+d) = 7+4 = 11
Hence, the terms are :-
3, 7, 11