21\lim_{x\rightarrow \infty } \frac{x^{3}(2a+b-3c) + x^{2}(5b-a-c)-b}{x^{4}(5a-b+4c)+x(5-a)+x^{2}(2) +c}=1
now dividing numerator and denominator by x2
\lim_{x\rightarrow \infty } \frac{x(2a+b-3c) +(5b-a-c)-b/x^{2}}{x^{2}(5a-b+4c)+(5-a)/x +(2) +c/x^{2}}=1
now since the limit is finite so we must hav
2a+b-3c=0.....................i
and 5a-b+4c=0...............ii
and we know tat since x→∞
so -b/x2 →0
(5-a)/x→0
c/x2→0
and (5b-a-c)/2 =1.................iii
solve eq i ,ii,and iii
