Question

Các bạn giup mik câu này vs

Answer 1

b) \(\left(x-1\right)\left(x^2+x+1\right)-x\left(x+2\right)\left(x-2\right)=5\)

\(x^3-1^3-x\left(x^2-4\right)=5\)

\(x^3-1-\left(x^3-4x\right)=5\)

\(x^3-1-x^3+4x=5\)

\(-1+4x=5\)

\(4x=6\)

\(x=\dfrac{3}{2}\)

Answer 2

\(\left(x-1\right)\left(x^2+x+1\right)-x\left(x+2\right)\left(x-2\right)=5\)

\(\Leftrightarrow x^3-1-x^3+4x=5\)

\(\Leftrightarrow4x=6\)

hay \(x=\dfrac{3}{2}\)