Question

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

Answer 1

câu a x = 7

Câu b x = -0,5

k nha

Answer 2

\(\text{a , (x-3).(x^2+3x+9)+x(x+2).(2-x)=1 }\)

=(x³-3³)+x(4-x²)=1

=x³-27+4x-x³=1

4x-27=1

4x=28

x=7

\(\text{b, (x+1)^3-(x-1)^3-6.(x-1)^2=-10}\)

=-0,5

Answer 3

trả lo nhanh nhen mik con` lamf bt nữa nha

Answer 4

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

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

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

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

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

\(\Leftrightarrow4x=1+27\)

\(\Leftrightarrow4x=28\)

\(\Leftrightarrow=7\)

Answer 5

a) ( x - 3 )( x² + 3x + 9 ) + x( x + 2 )( 2 - x ) = 1

<=> ( x³ - 27 ) + x( 2 + x )( 2 - x ) = 1

<=> x³ - 27 + x( 4 - x² ) = 1

<=> x³ - 27 + 4x - x³ = 1

<=> 4x - 27 = 1

<=> 4x = 28

<=> x = 7 

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

<=> x³ + 3x² + 3x + 1 - ( x³ - 3x² + 3x - 1 ) - 6( x² - 2x + 1 ) = -10

<=> x³ + 3x² + 3x + 1 - x³ + 3x² - 3x + 1 - 6x² + 12x - 6 = -10

<=> 12x - 4 = -10

<=> 12x = -6

<=> x = -6/12 = -1/2