SOLUTION: Hi! Use the substitution method to find all solutions of the system of equations. (Round each answer to two decimal places.) {x^2+y^2=25 y =2x thanks for the homewo

Algebra ->  Systems-of-equations -> SOLUTION: Hi! Use the substitution method to find all solutions of the system of equations. (Round each answer to two decimal places.) {x^2+y^2=25 y =2x thanks for the homewo      Log On


   

Question 200159: Hi!
Use the substitution method to find all solutions of the system of equations. (Round each answer to two decimal places.)
{x^2+y^2=25
y =2x
thanks for the homework help!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2%2By%5E2=25 Start with the first equation.


x%5E2%2B%282x%29%5E2=25 Plug in y=2x


x%5E2%2B4x%5E2=25 Square 2x to get 4x%5E2


5x%5E2=25 Combine like terms.


x%5E2=25%2F5 Divide both sides by 5.


x%5E2=5 Reduce


x=sqrt%285%29 or x=-sqrt%285%29 Take the square root of both sides (don't forget the "plus/minus"


The solutions above approximate to: x=2.236 or x=-2.236


which rounded to the nearest hundredth are: x=2.24 or x=-2.24


Now simply plug these values into y=2x to find the corresponding y values to the given x values. I'll let you take over from here.