Bài giải:
a) (2x2 + 3y)3 = (2x2)3 + 3(2x2)2 . 3y + 3 . 2x2 . (3y)2 + (3y)3
= 8x6 + 3 . 4x4 . 3y + 3 . 2x2 . 9y2 + 27y3
= 8x6 + 36x4y + 54x2y2 + 27y3
b) (1212x – 3)3 = (12x)3(12x)3- 3(12x)2(12x)2. 3 + 3(12x)(12x). 32 - 33
= 1818x3 – 3 . 1414x2 . 3 + 3 . 1212x . 9 – 27
= 1818x3 – 9494x2 + 272272x - 27
a) (2x2 + 3y)3 = (2x2)3 + 3(2x2)2 . 3y + 3 . 2x2 . (3y)2 + (3y)3
= 8x6 + 3 . 4x4 . 3y + 3 . 2x2 . 9y2 + 27y3
= 8x6 + 36x4y + 54x2y2 + 27y3
b) (1212x – 3)3 = (12x)3(12x)3- 3(12x)2(12x)2. 3 + 3(12x)(12x). 32 - 33
= 1818x3 – 3 . 1414x2 . 3 + 3 . 1212x . 9 – 27
= 1818x3 – 9494x2 + 272272x - 27
a) \(\left(2x^2+3y\right)^3\) = \(\left(2x^2\right)^3+3.\left(2x^2\right)^2.3y+3.2x^2.\left(3y\right)^2+\left(3y\right)^3\)
= \(8x^6+\left(36x^4\right)y+54x^2y^2+27y^3\)
b) \(\left(\dfrac{1}{2}x-3\right)^3\) = \(\left(\dfrac{1}{2}x\right)^3-3.\left(\dfrac{1}{2}x\right)^2.3+3.\dfrac{1}{2}x.3^2-3^3\)
= \(\dfrac{1}{8}x^3-\dfrac{9}{4}x^2+\dfrac{27}{2}x-27\)
a) (2x2+3y)3=(2x2)3+3.(2x2)2.3y+3.2x2.(3y)3
=8x6+36x4y+54x2y2+27y3
b) (\(\dfrac{1}{2}\)x-3)3=(\(\dfrac{1}{2}\)x)3-3.(\(\dfrac{1}{2}\)x)2.3+3.\(\dfrac{1}{2}\)x.32-33
=\(\dfrac{1}{8}\)x3-\(\dfrac{9}{4}\)x2+\(\dfrac{27}{2}\)x-27
a) (2x2 + 3y)3 = (2x2)3 + 3(2x2)2 . 3y + 3 . 2x2 . (3y)2 + (3y)3
= 8x6 + 3 . 4x4 . 3y + 3 . 2x2 . 9y2 + 27y3
= 8x6 + 36x4y + 54x2y2 + 27y3
b) (1212x – 3)3 = (12x)3(12x)3- 3(12x)2(12x)2. 3 + 3(12x)(12x). 32 - 33
= 1818x3 – 3 . 1414x2 . 3 + 3 . 1212x . 9 – 27
= 1818x3 – 9494x2 + 272272x - 27
