Question

rút gọn đa thức:
a(x+1)(x-1)
b(x+1)(x-1)(x²+1)
c(x+1)(x-1)(x²+1)(x⁴+1)-x⁸

Answer 1

a) \(\left(x+1\right)\left(x-1\right)\)

\(=x^2-1^2\)

\(=x^2-1\)

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

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

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

\(=x^4-1\)

c) \(\left(x+1\right)\left(x-1\right)\left(x^2+1\right)\left(x^2+1\right)-x^8\)

\(=\left(x^2-1\right)\left(x^2+1\right)\left(x^4+1\right)-x^8\)

\(=\left(x^4-1\right)\left(x^4+1\right)-x^8\)

\(=\left(x^4\right)^2-1-x^8\)

\(=x^8-1-x^8\)

\(=-1\)