Question

Giúp mk nha

Tìm x ( Đưa các biểu thức đã cho về dạng A(x).B(x)=0 )

a.x^3-x=0

b.x^3+x=0

c.x^2-4x=0

d.x(x-1)-2(1-x)=0

e.2x(x-2)-(2-x)^2=0

f.4x(x+1)=8(x+1)

g.5x(x-20)-x+2=0

h.(x+1)=(x+1)^2

Answer 1

a.\(x^3-x=0 \)

\(x(x^2-1)=0\)

x=0 hay x²-1=0

x=0 hay x²=1

x=0 hay x=1

Vậy x=0 hay x=1

b.\(x^3+1=0\)

\(x(x^2+1)=0\)

\(x=0 hay x^2+1=0\)

\(x=0 hay x^2=-1\)(vô lí vì x²≥0)

Vậy x=0

c.\(x^2-4x=0\)

\(x(x-4)=0\)

x=0 hay x-4=0

x=0 hay x=4

Vậy x=0 hay x=4

d.\(x(x-1)-2(1-x)=0\)

\(x(x-1)+2(x-1)=0 \)

\((x-1)(x+2)=0\)

x-1=0 hay x+2=0

x=1 hay x=-2

Vậy x=1 hay x=-2

e.\(2x(x-2)-(2-x)^2=0\)

\(2x(x-2)+(x-2)^2=0\)

\((x-2)(2x+x-2)=0\)

\((x-2)(3x-2)=0\)

x-2=0 hay 3x-2=0

x=2 hay 3x=2

x=2 hay x=2/3

Vậy x=2 hay x=2/3

f.\(4x(x+1)=8(x+1)\)

\(4x(x+1)-8(x+1)=0\)

\(4(x+1)(x-2)=0\)

_{4(x+1)=0 hay x-2=0}

_{x+1=0 hay x=2}

_{x=-1 hay x=2}

_{Vậy x=-1 hay x=2}

_{g.\(5x(x-2)-x+2=0\)}

\(5x(x-2)-(x-2)=0\)

\((x-2)(5x-1)=0\)

x-2=0 hay 5x-1=0

x=2 hay 5x=1

x=2 hay x=1/5

Vậy x=2 hay x=1/5

h.\((x+1)=(x+1)^2\)

\((x+1)-(x+1)^2=0\)

\((x+1)(1-x-1)=0\)

\((x+1)(-x)=0\)

x+1= 0 hay -x=0

x=-1 hay x=0

Vậy x=-1 hay x=0