In an arithmetic sequence {an}, a1 +a11 = 2019. Find a6. Help. 40 Pts

Work Shown:

a1 = unknown = x

a2 = x+d, where d is some constant

a3 = x+2d

a4 = x+3d

a5 = x+4d

a6 = x+5d

and so on until we reach

a11 = x+10d

Add a1 and a11 to get

a1+a11 = x+x+10d = 2x+10d = 2(x+5d)

Note how we get 2(x+5d) and above shows a6 = x+5d

So we see that a1+a11 is exactly double that of a6

This means a6 must be half that of a1+a11

If a1+a11 = 2019, then a6 = (a1+a11)/2 = 2019/2 = 1009.5

salary

step-by-step explanation: