# maths

posted by .

x is a number such that x2+3x+9=0. What is the value of x3?

• maths -

since (x-3)(x^2+3x+9) = x^3 - 3^3
x^3 - 3^3 = 0
x^3 = 27

• WoW at Steve - maths -

What a great way to do this question.

Did you see the round-about way I used ??
http://www.jiskha.com/display.cgi?id=1360597831

I was even thinking of using DeMoivre's theorem.

• WoW at Reiny - maths -

I was going to show an alternative direct solution, but when I saw where it was headed, I blew it off.

Can't believe you
(a) slogged through it all
(b) got it right!

## Similar Questions

1. ### Maths

Find the two digit number such that if you treble it and you take away four times the reverse of that number, the ansswer will be 8.
2. ### maths

N is an even 3-digit number such that the last 3 digits of N*N are N itself. What is the value of N?
3. ### Maths

(a) find d largest four digit number which has a total of exactly 3 factors. Assuming that one and the number itself are factors. (b) find a and b greater than zero such that a^2=b^3. (c) find. x and y such that x^3 + y^3 =1729
4. ### Maths question

(a) find the largest four digit number which has a total of exactly 3 factors assuming that one and d number itself are factors. (b) find a and b greater than zero such that a^2 = b^3. (c) find x and y such that x^3 y^3 =1729
5. ### maths

find value of p such that the equation (x+1)(x+2)=p
6. ### maths

Ramesh buys 150 shares of par value ` 10/- each of a company which pays annual dividend of 15% at such a price that he receives 10% on his investments. What is the market value of share?
7. ### Maths

I have a three digit number such that the sum of the cubes of each digit number containing the same digits. Find my number
8. ### maths

The function f is such that f(x)= (2 - x)^2, x belongs to real number. Find g and h as functions of x such that gh(x)=f(x)
9. ### Maths

If P and Q are two integers such that `P' is the predecessor of Q, what is the value of P- Q?
10. ### maths

1)find rational number a and b such that 2+5root7/2-5root7=a+root7 b 2)find the value of x if 5 pwer 2 square 9=(125)x 3)if a=9 b=root17 then find the value of (a power2- b power2)-1/3

More Similar Questions