If _ x ( x^2+x+1 x+1 -a x-b )=4 then

Step-by-step solution

aligned & _ x ( x^2+x+1 x+1 - a x- b )=4 & _ x ( x^2+x+1- ax (x+1)- b (x+1) x+1 )=4 & _ x [ (1- a ) x^2+(1- a - b ) x+(1- b ) x+1 ]=4 aligned Limit is finite, it exists when (1-a)=0 array cc & 1-a=0 & a=1 array array ll & _ x [ 1-a-b+ (1-b) x 1+ 1 x ]=4 & 1-a-b=4 & ~b =-4 & a=1, b=-4 array