Question

the 21st term of an AP the first 2 term are -3 &4

Answer 1

a = - 3

d = T2 - T1

d = 4 - (-3)

d = 4 + 3

d = 7

T21 = a + 20 d

= - 3 + 20(7)

= - 3 + 140

= 137

Answer 2

a=(-3),
d=4-(-3)= 4+3=7

a21= a+20d
-3 + 20*7
= -3 + 140
= 137