Posted by MATHS on Saturday, June 11, 2011 at 2:22pm.
solve to find x and y:
x^3+8y^3+x+2y=0

question (doubt)....  Reiny, Saturday, June 11, 2011 at 4:43pm
try grouping
(x+2y)(x^2  2xu + 4y^2) + (x+2y) = 0
(x+2y)(x^2  2xy + 4y^2 + 1) = 0
x = 2y or x^2 2xy + 4y^2 + 1 = 0
treat the second like a quadratic with
a=1
b=2y
c=4y^2+1
x = (2y ± √(4y^2  4(1)(4y^2+1))/2
= (2y ± √(12y^2  4)/2
notice the inside of the √ will always be negative so there is no real solution to that second part
so x = 2y
from that you can find an infinite number of solutions,
e.g. (2,1), (4,2), (5.2 , 2.6) ...
Answer This Question
Related Questions
 english  Im completly lost in this one. Im suppose Answer the following: ...
 Math  Guys please help me with this Trigonometry question based on De Moivre's ...
 MATH PLEASEEEEE  I have a question, if f(x)=x/2 and g(x)=3x+1 find: a) (f+g)(x...
 Algebra  Question 1 Solve using the multiplication principle then graph. 15>...
 Criminal Procedure  proof beyond a reasonable doubt in a criminal case to ...
 Music  Hello my teacher gave us question and he said to find our from any where...
 Algebra  Solve graphically. xy=0 y=x² The reason I don't understand the ...
 maths  my exams are starting from next week i am facing so much problems in ...
 English  To look with admiration at someone or something is to ______ but to ...
 geometry  line BD bisects angle ABC. Solve for X and find the measures of angle...
More Related Questions