Đáp án:
Giải thích các bước giải:
(3x+1)²=(3x)²+2.3x.1+1²=9x²+6x+1
(3x-4)²=(3x)²-2.3x.4+4²=9x²-24x+16
(3x-4)(3x+4)=(3x)²-4²=9x²-16
(3x+1)³=(3x)³+3.(3x)².1+3.3x.1²+1³=27x³+27x+9x+1
(3x-4)³=(3x)³+3.(3x)².4+3.3x4²+4³=27x³-108x+94x-64
(3x+1)(9x²-3x+1)=(3x)³+1³=27x³+1
(3x-4)(9x²-12x+16)=(3x)³-4³=27x³-64