Đáp án:
$\displaystyle \begin{array}{{>{\displaystyle}l}} 1) \ 9+12x+4x^{2}\\ 2) \ \frac{1}{16} +\frac{1}{2} k+k^{2}\\ 3) \ 25p^{2} -10pq+q^{2}\\ 4) \ 25-30x+9x^{2}\\ 5) \ ( 3x+2y)( 3x-2y)\\ 6)\left( x^{2} -\frac{1}{2}\right)\left( x^{2} +\frac{1}{2}\right) \end{array}$
Giải thích các bước giải:
$\displaystyle \begin{array}{{>{\displaystyle}l}} 1) \ \ ( 3+2x)^{2} =9+12x+4x^{2}\\ 2) \ \left(\frac{1}{4} +k\right)^{2} =\frac{1}{16} +\frac{1}{2} k+k^{2}\\ 3) \ \ ( 5p-q)^{2} =25p^{2} -10pq+q^{2}\\ 4) \ \ ( 5-3x)^{2} =25-30x+9x^{2}\\ 5) \ \ 9x^{2} -4y^{2} =( 3x+2y)( 3x-2y)\\ 6) \ \ x^{4} -\frac{1}{4} =\left( x^{2} -\frac{1}{2}\right)\left( x^{2} +\frac{1}{2}\right) \end{array}$
