SOLUTION: Find two numbers whose sum is 10 and whose squares differ by 20

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Find two numbers whose sum is 10 and whose squares differ by 20      Log On


   

Question 76746This question is from textbook
: Find two numbers whose sum is 10 and whose squares differ by 20 This question is from textbook

Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
X+Y=10, X=10-Y
X^2-Y*2=20 NOW SUBSTITITE (10-Y) FOR X & SOLVE FOR Y IN THE SECOND EQUATION
(10-Y)^2-Y^2=20
100-20Y+Y^2-Y^2=20
-20Y=20-100
-20Y=-80
Y=-80/-20
Y=4 ANSWER.
X+4=10
X=10-4
X=6 ANSWER.
PROOF
6^2-4^2=20
36-16=20
20=20