Question

Find the first three terms of AP whose second term is 12 and 7th term exceeds the 4th term by 15.​

Answer 1

Answer:

Given :

Second term is 12th and 7th term exceeds the 4th term by 15

To Find :

Find AP

Solution:

Formula of nth term :

an = a + (n − 1)d

Where d is common difference

n = no. of terms

a = first term

Substitute n = 2

a2 = a + (2-1)d = a + d

We are given that second term is 12

So,a+d=12 ---- 1

Substitute n=7

a7 = a + (7 −1)d = a + 6d

Substitute n = 4

a4 = a + (4-1)d = a + 3d

We are given that 7th term exceeds the 4th term by 15

So, a+6d-a-3d=15

3d=15

d=5

Substitute the value of d in 1

So,a+5=12

a=12-5=7

a=7

AP : a,a+d,a+2d,....=5,7+5,7+2(5),....=7,12,17,....

So, AP: 7,12,17,....

#BrainlyLock .