Question

[Đan Vy]

Tìm x:

( 4x + 1 )( 16x^2 - 4x + 1 ) - 16x ( 4x^2 - 5 ) = 17

Tính giá trị biểu thức:

p=(x+1)(x^2-x+1)+x-(x-1)(x^2+x+1)+2010; x=-2010)

q=16x(4x^2-5)-(4x+1)(16x^2-4x+1); x=1/5

Answer 1

[T.Thùy Ninh]

\(p=\left(x+1\right)\left(x^2-x+1\right)+x-\left(x-1\right)\left(x^2+x+1\right)+2010\)\(=\left(x^3+1\right)+x-\left(x^3-1\right)+2010=x^3+1+x-x^3+1+2010=x+2012\)Với \(x=-2010\Rightarrow p=-2010+2012=2\)

\(q=16x\left(4x^2-5\right)-\left(4x+1\right)\left(16x^2-4x+1\right)=64x^3-80x-64x^3-1=-80x-1\)Với \(x=\dfrac{1}{5}\Rightarrow q=-80.\dfrac{1}{5}-1=-17\)