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

\(=x^3\left(x+1\right)-8\left(x+1\right)=\left(x+1\right)\left(x^3-8\right)\)

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

\(x^4-2x^3+x^2-2x\)

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

\(\dfrac{1}{3}\cdot x+\left(\dfrac{2}{3}-\dfrac{4}{9}\right)=-\dfrac{3}{4}\)

                       \(\dfrac{1}{3}x=-\dfrac{3}{4}-\left(\dfrac{2}{3}-\dfrac{4}{9}\right)\)

                       \(\dfrac{1}{3}x=-\dfrac{35}{36}\)

                          \(x=3\cdot\left(\dfrac{-35}{36}\right)\)

                          \(x=-\dfrac{35}{12}.\)

\(Vậy...\)

\(\left(\dfrac{5}{6}-\dfrac{3}{2}\right):\left(\dfrac{-2x}{3}\right)=-\dfrac{12}{19}\)

                             \(19=-x\cdot12\)

                     \(-x\cdot12=19\)

                              \(x=-\dfrac{19}{12}.\)

\(Vậy...\)

\(a.A=\left(x+y\right)^2-\left(x-y\right)^2=x^2+2xy+y^2-x^2+2xy-y^2\)

\(=x^2-x^2+2xy+2xy+y^2-y^2=4xy.\)

\(b.B=\left(x+2\right)^2+2\left(x+2\right)\left(x-3\right)+\left(x-3\right)^2\)

\(=x^2+4x+4+2x^2-2x-12+x^2-6x+9\)

\(=x^2+2x^2+x^2+4x-2x-6x+4-12+9\)

\(=4x^2-4x+1.\)

\(c.C=\left(x+2\right)^2-2\left(x+2\right)\left(x+3\right)+\left(x+3\right)^2\)

\(=x^2+4x+4-2x^2-10x-12+x^2+6x+9\)

\(=x^2-2x^2+x^2+4x-10x+6x+4-12+9\)

\(=1.\)

\(C=\left(x+2\right)^2-2\left(x+2\right)\left(x+3\right)+\left(x+3\right)^2\)

\(=x^2+4x+4-2x^2-10x-12+x^2+6x+9+\)

\(=x^2-2x^2+x^2+4x-10x+6x+4-12+9\)

\(=1.\)

ko có gì.😁

lx