# Another linear system

• April 29th 2009, 04:45 AM
nmound
Another linear system
y=2x+4
10x-5y=-20

i know using the substitution method plays out like so...
10x-5(2x+4)=-20
10x-10x-20=-20
10x-10x=0
0=0

I have to express the answer in interval notation....how would I do that, and since the answer is 0=0 is their a value for x and y at all
• April 29th 2009, 05:14 AM
masters
Quote:

Originally Posted by nmound
y=2x+4
10x-5y=-20

i know using the substitution method plays out like so...
10x-5(2x+4)=-20
10x-10x-20=-20
10x-10x=0
0=0

I have to express the answer in interval notation....how would I do that, and since the answer is 0=0 is their a value for x and y at all

Hi nmound,

The second equation is a multiple of the first equation making them the same line. There is an infinite number of solutions. We call this system "consistent and dependent".

Solution: $(- \infty, + \infty)$