Consider an A.p. a₁, a₂, a₃, ....... such that a₃+a₅+a₈=11 and a₄+a₂= –2, then the value of a₁+a₆+a₇ is

a+2d+a+4d+a+7d = 11 $\Rightarrow$ 3a+13d=11..........(1)
$\Rightarrow$a+3d+a+d=–2 $\Rightarrow$ a+2d = –1.....(2)
from (1) and (2) $\Rightarrow$ a= –5, d= 2 $\Rightarrow$ a₁+a₆+a₇ = 7