Câu hỏi của duyên

Question

Bài 1 thực hiện phép tính

a)$\left(3x^2-2y\right)^3$

b)$\left(5+3x\right)^3$

Cheewin · Accepted Answer

a) $\left(3x^2-2y\right)^3$

$=\left(3x^2\right)^3-\left(3x^2\right)^2.2y+3x^2.\left(2y\right)^2-\left(2y\right)^3$

$=27x^6-18x^4y+12x^2y^2-8y^3$

b) $\left(5+3x\right)^3$

$=5^3+5^2.3x+5.\left(3x\right)^2+\left(3x\right)^3$

$=125+75x+45x^2+27x^3$Câu trả lời: a) $\left(3x^2-2y\right)^3$

$=\left(3x^2\right)^3-\left(3x^2\right)^2.2y+3x^2.\left(2y\right)^2-\left(2y\right)^3$

$=27x^6-18x^4y+12x^2y^2-8y^3$

b) $\left(5+3x\right)^3$

$=5^3+5^2.3x+5.\left(3x\right)^2+\left(3x\right)^3$

$=125+75x+45x^2+27x^3$

Hiep Van · Answer

a) ( 3x2 - 2y )3

= ( 3x2)3 - ( 3x2)2. 2y + 3x2 .( 2y)2 - ( 2y)3

= 27x6 - 9x4 . 2y + 3x2 . 4y2 - 8y3

= 27x6 - 18x4y + 12x2y2- 8y3

b) ( 5 + 3x )3

= 53 + 52 . 3x + 5 . (3x)2 + (3x)3

= 125 + 25 . 3x + 5 . 9x2 + 27x3

= 125 + 75x + 45x2 + 27x3Câu trả lời: a) ( 3x2 - 2y )3