Question

Giải pt

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

Answer 1

\(\Rightarrow2x\left(x+2\right)\left(x+2\right)-8x^2=2\left(x^3-8\right).\)

\(\Rightarrow\left(2x^2+4\right)\left(x+2\right)-8x^2=2x^3-8\)

\(\Rightarrow2x^3+4x^2+4x+8=2x^2-8\)

\(\Rightarrow2x^3+4x^2-2x^2+4x=-8-8\)

\(\Rightarrow2x^3+2x^2+4x=-16\)

\(\Rightarrow2x\left(x^2+x+2\right)=-16\)tự giải tiếp nhé!

Answer 2

\(\Rightarrow x=-2\)

Answer 3

2x(x+2)^2-8x^2=2(x-2)(x^2+2x+4)

2x(x^2+4x+4)-8x^2=2(x^3-8)

2x^3+8x^2+8x-8x^2=2x^3-16

2x^3-2x^3+8x^2-8x^2+8x=-16

8x=-16

x=-2 

Vay pt co tap nghiem la :S={-2}