Answer:
a) The first term is a=7
b) The common difference is d=3
c) The sum of the first 15 term is 420.
Step-by-step explanation:
Given : If the fifth term of a AP is 19 and the tenth term is 34.
To find : a) the first term b) The common difference c) The sum of the first 15 term ?
Solution :
The Arithmetic progression is in the form,
Where, a is the first term and d is the common difference
The nth term of the A.P is
The fifth term of a AP is 19.
...(1)
The tenth term is 34.
...(2)
Solving (1) and (2) by subtracting the equations,
Substitute in (1),
a) The first term is a=7
b) The common difference is d=3
c) The sum of the first 15 term is given by,
The sum of the first 15 term is 420.