Question

Bài 2 tính 

a) (x+1)³-x(x-2)²-1

Answer 1

(x + 1)³ - x(x - 2)² - 1

= x³ + 3x² + 3x + 1 - x(x² - 4x + 4) - 1

= x³ + 3x² + 3x + 1 - x³ + 4x² - 4x - 1

= x³ - x³ + 3x² + 4x² + 3x - 4x + 1 - 1

= 7x² - x 

Answer 2

\(\left(x+1\right)^3-x\left(x-2\right)^2-1=x^3+3x^2+3x+1-x^3+4x^2-4x-1=7x^2-x\)

Answer 3

= \(x^3+3x^2+3x-x\left(x^2-4x+4\right)-1\)

= \(x^3+3x^2+3x+1-x^3+4x^2-4x-1\)

=\(7x^2-x\)

Answer 4

\(\left(x+1\right)^3-x\left(x-2\right)^2-1\)

\(=x^3+3x^2+3x+1-x^3+4x^2-4x-1\)

\(=7x^2-x\)

Answer 5

ok

 

Answer 6

ok