SOLUTION: A number is twice another number and the sum of their squares is 80. Find the numbers.

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Question 1040785: A number is twice another number and the sum of their squares is 80. Find the numbers.
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.
x = 2y,
x^2 + y^2 = 80.

--->

4y^2 + y^2 = 80  -->   5y^2 = 80  -->  y^2 = 80/5 = 16  -->  y = +/-4.

y = +-2.

Answer:  The numbers are  4 and 8  or  -4 and -8.