Question

if an AP have 8 as it's first term and -5 as a common difference and it's first three terms are 8,A, B then (a+b) is equal to
1) 0
2) -1
3) 1
4) 2
and justify your answer​

Answer 1

Answer:

If the first three terms of an AP are 8, A and B, and the common difference is -5, then (a+b) is 1

Step-by-step explanation:

Given
The first term of the AP =8
Common difference d = -5

Given a is the second term
So, a = 8+(-5) = 8-5 = 3

Given b is the second term
So, b= 3+(-5) = 3-5 = -2

So (a+b) = 3+(-2) = 3-2 = 1

So , the answer is 1

Answer 2

Answer:

Option 3 is correct answer

Step-by-step explanation:

Given data

AP have 8 as first term, -5 as common difference

and first 3 terms are 8, A, B

here we need to find  A+B  

We know that in a AP nth term  $T_{n}$ = a + (n-1) d

from given data a = 8, d = -5

⇒ 2nd term (A) in given AP = $T_{2}$ = 8 + (2-1) (-5)

                                                = 8 -5 = 3

⇒ 3rd term (B) in given AP = $T_{3} =$ 8 + (3-1) (-5)

                                               = 8 + (2)(-5)

                                               = 8 - 10 = -2

⇒  A = 3, B = -2 ⇒ A + B =  3 + (-2) = 3-2 = 1

⇒ correct answer from options is (3)   ⇒ 1