Question

can anyone answer this ​

Answer 1

Answer:

y=13 then x+y=16

so x+13=16

x=3

Answer 2

Step-by-step explanation:

5+(−41)+9+(−39)+13+(−37)+17+....+(−5)+81+(−3)

The given series is combination of two AP's.

Let A1=5+9+13+.....+77+81

and A2=−41−39−37−......(−3)

For A1:

First term =a=5

Common difference=d=2

Last term =l=81

Now, using formula:

81=5+(n−1)4

n=20

Thus, there are 20 terms in AP.

Now,

Find the sum of these 76 terms:

S20=n/2[a+l]

=20/2(5+81)

=860

Sum of 20 terms of this AP is 860.

For A2:

First term =a=−41

Common difference =d=2

Last term=l=3

Now, using formula:

−3=−41+(n−1)2

n=20

Thus, there are 20 terms in AP.

Now,

Find Sum of these 76 terms:

S20=n/2[a+l]

=20/2(−41−3)