Đáp án:
$A= 515$
$B= -48$
Giải thích các bước giải:
$A= \left ( 2x-3 \right )^{2}-\left ( x-3 \right )^{3}+\left ( 4x+1 \right )\left ( 16x^{2}-4x+1 \right )\left ( x= 2 \right )$
$\Rightarrow A= \left ( 2.2-3 \right )^{2}-\left ( 2-3 \right )^{3}+\left ( 4.2+1 \right )\left ( 16.2^{2}-4.2+1 \right )$
$= 1^{2}-\left ( -1 \right )^{3}+9.57$
$= 515$
$B= \left ( 3x-y \right )^{3}-\left ( x+2y \right )\left ( x^{2}-2xy+4y^{2} \right )+\left ( 3+x \right )^{2}$
tại $x=1,y=2$
$\Rightarrow B= \left ( 3.1-2 \right )^{3}-\left ( 1+2.2 \right )\left ( 1^{2}-2.2.1+4.2^{2} \right )+\left ( 3+1 \right )^{2}$
$\Rightarrow B= 1^{3}-5.13+4^{2}= -48$
