Rút gọn biểu thức \(A = {{\left( {9{x^2} + 12x + 4} \right).\left( {3x - 2} \right)} \over {\left( {3x + 2} \right)}}\)
Giải chi tiết:
\(A = {{\left( {9{x^2} + 12x + 4} \right).\left( {3x - 2} \right)} \over {\left( {3x + 2} \right)}} = {{\left( {{{\left( {3x} \right)}^2} + 2.3x.2 + {2^2}} \right)\left( {3x - 2} \right)} \over {\left( {3x + 2} \right)}} = {{{{\left( {3x + 2} \right)}^2}\left( {3x - 2} \right)} \over {\left( {3x + 2} \right)}} = \left( {3x + 2} \right)\left( {3x - 2} \right) = 9{x^2} – 4\)