Question

in an Ap if commom difference d=-4 and the seventh term a7 is 4 then find the first term

Answer 1

d=4 and A7=4
Now...,
A7 = 4
a+(n-1)d=4
a+(7-1)4=4
a+6×4=4
a+24=4
a=-20.....
Thus first term =-20
Hope this helps you.......

Answer 2

d= -4
a7 = a + (n-1)d
a+(7-1)*(-4)=4
a+6*(-4)=4
a-24=4
a=4+24
a=28