Question

Rut gon bieu thuc

(x+1)² - (x-1)² - 3. (x+1). (x-1)

Answer 1

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

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

Answer 2

nhầm

\(=4x-3x^2+3\) nhé

Answer 3

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

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

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

Answer 4

= (x+1+x-1)(x+1-x+1) - 3(x² -1)=

=4x - 3x² +3