Posted by parth on .
the first and second terms of an arithmetic progression are 161 and 154 respectively.the sumthe first m terms is zero.find the value of m

arithmetic 
Reiny,
a = 161
a+d = 154 , so d = 7
S(m) = (m/2)(2a + (m1)d)
0 = m/2(322  7m+ 7)
329m  7m^2=0
49m  m^2 = 0
m(49m)=0
m = 49