Question

The nth term of an A.P. is given by An =-4n+15. Find the 15th term and the common difference of the A.P. (Ans: a15 = -45, d = -4)

Answer 1

Answer:

15 th term = - 45

common difference = - 4

Step-by-step explanation:

=> An = - 4n + 15

=> a + ( n - 1 ) d = - 4n + 15

=> a + ( n - 1 ) d = 11 + ( n - 1 ) (-4)

comparing LHS and RHS

a = 11 and d = - 4

15th term = 11 + 14x(-4)

= 11 - 56

= - 45

Answer 2

Answer:

a15= -4×15+15

=-60+15

=-45