Question

Thực hiện phép tính:

a. ( x-2)^3- x(x+1)(x-1)+ 6x(x-3)

b.(x-2)(x^2-2x+4)(x+2)(x^2+2x+4)

Tìm x biết:

a.(x-3)(x^2+ 3x+9)+ x(x+2)(2-x)=1

b. (x+1)^3- (x-1)^3 - 6(x-1)^2=-10

help me. giúp mk vs

Answer 1

Câu 2: 

a: \(\left(x-3\right)\left(x^2+3x+9\right)+x\left(x+2\right)\left(2-x\right)=1\)

\(\Leftrightarrow x^3-27-x\left(x^2-4\right)=1\)

\(\Leftrightarrow x^3-27-x^3+4x=1\)

=>4x-27=1

=>4x=28

hay x=7

b: \(\left(x+1\right)^3-\left(x-1\right)^3-6\left(x-1\right)^2=-10\)

\(\Leftrightarrow x^3+3x^2+3x+1-\left(x^3-3x^2+3x-1\right)-6\left(x^2-2x+1\right)=-10\)

\(\Leftrightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6x^2+12x-6=-10\)

\(\Leftrightarrow12x-4=-10\)

=>12x=-6

hay x=-1/2