How to solve x - 2y =5, 2x -4y= 1 using substitution method

Solving the system using addition would be (x,y)= -9, 7 correct?

How would you solve this system using subtraction?

Substitution Method:

x - 2y = 5 ----> x = 2y + 5 {added 2y to both sides}
2x - 4y = 1

2x - 4y = 1 {bottom equation}
2(2y + 5) - 4y = 1 {substituted 2y + 5, in for x, into bottom equation}
4y + 10 - 4y = 1
10 = 1
= no solution

When the variable disappears and you get a false statement, such as 0 = 3,
then thee is "no solution". This means, the two lines would not intersect.
In other words, the two equations, when graphed, would create parallel lines.

When the variable disappears and you get a true statement, such as 0 = 0,
then there are "infinite solutions". This means, the two lines intersect
in an infinite number of points. In other words, the two equations are equivalent,
and would create the same line when graphed.

For more help like this, ask the house: http://www.algebrahouse.com

X -2y=5 x -2y=5
2x-4y=1 x -2(-1)=5
x + 2=5
-2(X )-2y=5 -2
2x-4y=1 x=3

-2x-2y=5
+ 2x-4y=1
___________

0-6y=6
_____
-6 y= -1




i think im right but i maybe all wrong

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