Sunday

September 21, 2014

September 21, 2014

Posted by **please help me out!!! please** on Monday, February 11, 2013 at 10:50am.

- algebra! -
**Reiny**, Monday, February 11, 2013 at 11:17amx^2 + 3x + 9 = 0

x = (-3 ±√-27)/2

= (-3 ± 3i√3)/2

if x = (-3 + 3i√3)/2

x^3 = (1/8)( -27 + 3(9)(3i√3) + 3(-3)(3i√3)^2 + (3i√3)^3 )

= (1/8)( -27 +81i√3 - 243i^2 + 81i^3√3)

= (1/8)( -27 + 81i√3 + 243 - 81√3i)

= (1/8)(216) = 27

if x = (-3 - 3√3i)/2

x^3 = (1/8)( -27 + 3(9)(-3√3i) +3(-3)(-3√3i)^2 + (-3√3)^3 )

=(1/8)( -27 - 81√3i -243i^2√3 + (-3√3i)^3 )

= (1/8)( -27 - 81√3i + 243 - 81√3i^3 )

= (1/8) (-27 - 81√3i + 243 + 81√3i )

=(1/8)(216) = 27

so x^3 = 27

**Answer this Question**

**Related Questions**

Algebra - Find the value of x such that the four-digit number x15x is divisible ...

Algebra - How do you find the excluded value if there is another variable or ...

algebra - How would you go about solving this? Im totally confused. Thanks! Find...

math - the sum of a number and 3 times that number is 76. what is that number? ...

Calculus - Let f be a twice-differentiable function such that f(2)=5 and f(5)=2...

****college algebra**** - Let h(x) = 3x + 4. For what value of x is (h o h)(x...

Math (algebra) - For every positive integer n, consider all monic polynomials f(...

****college algebra**** - Let g(x) = -2x + 8 and h(x) = 3x + 4. For what value ...

algebra - A pair of emirps consists of two prime numbers such that reversing ...

calculus - Let f(x) = (x+1)/(x-1). Show that there are no vlue of c such that f(...