Thực hiện phép tính: (a) (2x−7)^2. (b) (18a^2b^4−7a^3b+12a^2b^2):(3a^2b).

a) \[\begin{array}{l}\,\,\,{\left( {2x - 7} \right)^2}\\ = \,{(2x)^2} - 2.2x.7 + {7^2}\\ = \,4{x^2} - 28x + 49\end{array}\]

b) \(\left( {18{a^2}{b^4} - 7{a^3}b + 12{a^2}{b^2}} \right):\left( {3{a^2}b} \right) = 6{b^3} - \frac{7}{3}a + 4b.\)

c) \(\left( {x - 5} \right)\left( {3{x^2} - 4x + 2} \right).\)

\[ = 3{x^3} - 4{x^2} + 2x - 15{x^2} + 20x - 10\]

\[ = 3{x^3} - 19{x^2} + 22x - 10\]