Question

Giải phương trình : (x - 1)^3 - x(x + 1)^2 = 5x(2 - x) - 11(x + 2)

Answer 1

\(\left(x-1\right)^3-x\left(x+1\right)^2=5x\left(2-x\right)-11\left(x+2\right)\)

\(\Leftrightarrow\left(x^3-3x^2+3x-1\right)-x\left(x^2+2x+1\right)=10x-5x^2-11x-22\)

\(\Leftrightarrow x^3-3x^2+3x-1-x^3-2x^2-x=-x-5x^2-22\)

\(\Leftrightarrow-5x^2+2x-1=-5x^2-x-22\)

\(\Leftrightarrow-5x^2+5x^2+2x+x=1-22\)

\(\Leftrightarrow3x=-21\Leftrightarrow x=-7\)

Vậy \(x=-7\)

Answer 2

\(\left(x-1\right)^3-x\left(x+1\right)^2=5x\left(2-x\right)-11\left(x+2\right)\)

\(\Leftrightarrow\left(x^3-3x^2+3x-1\right)-x\left(x^2+2x+1\right)=10x-5x-11x-22\)

\(\Leftrightarrow x^3-3x^2+3x-1-x^3-2x^2-x=-x-5x^2-22\)

\(\Leftrightarrow-5x^2+2x-1=-5x^2-x-22\)

\(\Leftrightarrow-5x^2+5x^2+2x+x=1-22\)

\(\Leftrightarrow3x=-21\Leftrightarrow x=-7\)

Vậy \(x=-7\)

Answer 3

có làm mới có ăn nhé