The sum of 7th and 10th term of an A.P. is 50 and aum of 8th and 12th terms is 80. Find the first three terms of their A.P.
Answers
Answered by
0
using eq. a+(n-1)d
a+6d+a+9d=50
2a+15d=50
similarly,a+7d+a+11d=80
2a+18d=80
subtractiong the two obtained eqs.,we get 3d=30
hence d=10
substituting a= -50
hence first term is -50 second term is -50+10=-40 third term is -50+10+10=-30
Similar questions