4(x+1)mũ 2+(2x-1)mũ 2-8(x-1)(x+1)=11 nhờ các bn giúp mik

`4(x+1)^2 + (2x-1)^2-8(x-1)(x+1)=11`

`<=> 4(x^2+2x+1)+(4x^2-4x + 1) -8(x^2-1)=11`

`<=> 4x^2 + 8x + 4 + 4x^2-4x+1-8x^2+8=11`

`<=> 4x +13=11`

`<=> 4x =-2 `

`<=> x= -1/2`