Question

If 18,a,b,-3 are AP then find a+b

Answer 1

Answer:

Let p, be the first term i.e; 18

And, d, be the common difference,

From given series,

4th term =p+3d=−3

⟹18+3d=−3

Hence, d=−7

So, a=p+d=18−7=11

And, b=p+2d=18−14=4

Therefore,

a+b=11+4=15

Hope it helps

Answer 2

Answer:

Step-by-step explanation:

Let p, be the first term  i.e; 18

And, d, be the common difference,

From given series,

4th term =p+3d=−3

⟹18+3d=−3

Hence,  d=−7

So, a=p+d=18−7=11

And,  b=p+2d=18−14=4

Therefore,

a+b=11+4=15