Question

we have an arthmeting progressing with a15=5given that a12+a19 =13 find the common difference d=​

Answer 1

Answer:

a15 = 5

therefore, a+14d=5

a=5-14d. let us make it as equation 1.

now, a12+a19=13

(a+11d)+(a+18d)=13

therefore 2a+29d=13. let us make it as equation 2.

now putting equation 1 in equation 2.

therefore, 2(5-14d)+29d=13.

therefore, 10-28d+29d=13.

so, 10+d=13.

therefore, d=13-10

so, d= 3. this is the answer.

I hope that this is the correct answer and also helpful to you.