SOLUTION: Hello, I'm stumped on yet another problem... Solve the following nonlinear system by substitution: {{{ x^2+y^2=10 }}} {{{ -3x+y=0 }}} In advance, THANKS SO MUC

Algebra ->  Systems-of-equations -> SOLUTION: Hello, I'm stumped on yet another problem... Solve the following nonlinear system by substitution: {{{ x^2+y^2=10 }}} {{{ -3x+y=0 }}} In advance, THANKS SO MUC      Log On


   



Question 6846: Hello,

I'm stumped on yet another problem...

Solve the following nonlinear system by substitution:

+x%5E2%2By%5E2=10+
+-3x%2By=0+

In advance, THANKS SO MUCH for your assistance!!!

Answer by prabhjyot(165) About Me  (Show Source):
You can put this solution on YOUR website!
In the first equation both of the variables are squared and in the second equation both of the variables are to the first power. In other words, there is no way that we can use elimination here and so we are must use substitution
+x%5E2%2By%5E2=10+
+-3x%2By=0+
solve the second equation for y and substitute this into the first equation.
y = 3x
x^2 +(3x)^2 =10
x^2 +9x^2 =10
10x^2 =10
x^2 = 10/10=1
x^2=1
x= (sqrt(1))=+/- 1
So, we have two values of x. Now, we need to determine the values of y
We determine the values of y by plugging x into our substitution.
y=3x
y=3(-1)=-3
y=3(1) =3

Now, we only have two solutions here
We get y=3 as a solution ONLY if x= 1 and so the first solution is,
x = 1 , y=3
Likewise, we only get y=-3 ONLY if x = -1 and so the second solution is,
x=-1 ,y=- 3