#Up
~Bài tham khảo~:
a) (x+1)³=x³+3.x².1+3.x.1²+1³
= x³+3x²+3x+1
b) (x-2)³ =x³-3.x².2+3.x.2²-2³
= x³ - 6x²+12x-8
c) (x+1/3)³=x³+3.x².1/3+3.x.(1/3)²+(1/3)³
= x³+x²+1/3x+1/27
d) (2x-3)³=(2x)³-3.(2x)².3+3.2x.3²-3³
= 8x³-36x²+54x-27
e) x³-3x²+3x-1 = x³-3.x².1+3.x.1²-1³
= (x-1)³
f) 27x³+54x²+36x+8 = (3x)³+3.(3x)².2+3.3x.2²+2³
= (3x+2)³
g) 8x³+4x²+2/3x+1/27= (2x)³+3.(2x)².1/3+3.2x.(1/3)²+(1/3)³
= (2x+1/3)³
h) x³-9x² +27x-27=x³-3.x².3+3.x.3²-3³
= (x-3)³
Chúc em hc tốt!
(xin hay nhất ạ!)
