# Math Help - Linear systems

1. ## Linear systems

so this is the question....

x^2 +y^2=4
y=2x-5

how do i do this???? (show full steps please)

2. ## Re: Linear systems

Originally Posted by cheers
so this is the question....

x^2 +y^2=4
y=2x-5

how do i do this???? (show full steps please)
First this is not a linear system. It can be solved by substition

$x^2+(2x-5)^2=4$

This is a quadratic equation. Expand out the parenthesis and sput into standard form and solve.

Post back if you get stuck.

3. ## Re: Linear systems

Originally Posted by cheers
so this is the question....

x^2 +y^2=4
y=2x-5

how do i do this???? (show full steps please)
substitute $(2x-5)$ for $y$ in the circle equation ...

$x^2 + (2x-5)^2 = 4$

solve for x , then find y using the linear equation

note you may get more than one solution for x