Question

In an ap is the common difference is equal to minus 4and the seventh term
is 4 then find the first term

Answer 1

t7 = 4 ; d= -4

t7 = a+(n-1)d
4= a+(7-1)-4
4= a+(6)-4
4=a+(-24)
4=a -24
a= 24+4
a=28

a=T1
T1=28

first term of AP is 28