SOLUTION: Please help me solve this using the addition method. Thank you! {{{ x^2+y^2=17 }}} {{{ x^2-2y^2=-31 }}}

Algebra ->  Systems-of-equations -> SOLUTION: Please help me solve this using the addition method. Thank you! {{{ x^2+y^2=17 }}} {{{ x^2-2y^2=-31 }}}      Log On


   

Question 1061575: Please help me solve this using the addition method. Thank you!
+x%5E2%2By%5E2=17+
+x%5E2-2y%5E2=-31+
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Subtract eq. 2 from eq. 1,
x%5E2%2By%5E2-x%5E2%2B2y%5E2=17-%28-31%29
3y%5E2=48
y%5E2=16
y=4 and y=-4
So then,
x%5E2%2B16=17
x%5E2=1
x=1 and x=-1
(-1,4)
(-1,-4)
(1,4)
(1,-4)