Math, asked by ankit422, 1 year ago

aswer this question
find the comman difference
a21-a7=84

Answers

Answered by adityakraul9
0
21a - 7a = 84
14a = 84
a = 84/14
a = 6
Answered by ALTAF11
2
a21 can be written as a + 20d
a7 can be written as a + 6d

where a is first term
d is common difference

=> because an = a + ( n - 1 )d

a21 - a7 = 84

a + 20d - ( a + 6d ) = 84

a + 20d - a - 6d = 84

14d = 84

d = 6
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