Question

In an AP, if common difference d=3, then t7-t9 is equal to

Answer 1

Answer:

let a be the first term

given d =3

tn= a + (n-1) d

t7 = a + (7-1) (3)

t7 = a + 18

SIMILARLY

t9 = a + 24

$t_{ 7} - t_{9} = a + 18 - (a + 24) \\ = a + 18 - a - 24 \\ = - 6$

Answer 2

Answer:

d=3, ( given)

Step-by-step explanation:

tn = a + ( n-1) d

t7. = a + (7-1) 3

t7. = a + 18

Similarly, t9 = a + 24

t7 - t9 = a+18-(a+24)

= 18-24

= -6