Question

T18=7 and T7=18 obtain T25

Answer 1

Answer:

Step-by-step explanation:

T18=7

a+17d=7. eq1

T7=18

a+6d=18. eq2

From 1 and 2

d=-1

a=24

T25=a+24d

= 24 +24(-1)

= 0

Answer 2

d=7-18/18-7
=-11/11
=-1
hence
t7=a+(n-1)d
18=a-6
a=24
hence
t25=24+24(-1)
=24-24=0