Question

the term of an Ap are 4, a, b, -17 , then a-b is ?
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Answer 1

Answer:

I don't understand question

Answer 2

Answer:

a=first term of the AP,d=Common difference between the numbers of the AP

nth term=a+(n-1)d

=>4th term=4+(4-1)d

=>-17=4+3d

=>3d=-17-4

=>3d=-21

=>d=-21/3=-7

Therfore a=4+d=4+(-7)=4-7=-3

And b=a+d=-3+(-7)=-3-7=-10

Then a-b=-3-(-10)=-3+10=7 [Ans]