SOLUTION: Solve. y-8x=0 8x^2+y^2=72 I want to know how they got these answers: (1,8)(-1,-8) Thank you for your help.

Algebra ->  Systems-of-equations -> SOLUTION: Solve. y-8x=0 8x^2+y^2=72 I want to know how they got these answers: (1,8)(-1,-8) Thank you for your help.      Log On


   

Question 458746: Solve.
y-8x=0
8x^2+y^2=72
I want to know how they got these answers: (1,8)(-1,-8)
Thank you for your help.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
(1) +y+-+8x+=+0+
(2) +8x%5E2+%2B+y%5E2+=+72+
-----------------------
(1) +y+=+8x+
Substitute:
(2) +8x%5E2+%2B+%288x%29%5E2+=+72+
(2) +8x%5E2+%2B+64x%5E2+=+72+
(2) +x%5E2+%2B+8x%5E2+=+9+
(2) +9x%5E2+=+9+
(2) +x%5E2+=+1+
+x+=+1+
+x+=+-1+
and,
(1) +y+=+8%2A1+
+y+=+8+
and
(1) +y+=+8%2A%28-1%29+
+y+=+-8+
(1,8), (-1,-8)