Question

Find the coefficient x^7 in
\[\huge (ax^{2}+\frac{ 1 }{ bx })^{11}\]
and of x^ -7 in
\[\huge (ax-\frac{ 1 }{ bx^{2} })^{11}\]
and find the relation between "a" and "b" so that these coefficients are equal (where \[a,b \neq 0\]