Solve x − 2y = 6
3x − 6y = 18

Question

Solve x − 2y = 6
3x − 6y = 18

anonymous · Answer

(2, −2) 

 (3, negative three halves) 

 No solutions 

 Infinitely many solutions

anonymous · Answer

@iGreen

eric_d · Answer

x-2y=6
      x=6+2y...............1

3x-6y=18
        x=6+2y............2
Substitute 1 into 2 to find value of x first

eric_d · Answer

sorry, nt x but to find value of y

eric_d · Answer

what will u get @_angeliquexoxo

anonymous · Answer

I am actually confused... how do I find the value of y?

jumperman · Answer

Well you need to get y by itself right?

jumperman · Answer

Don't you use the inverse of operations for that?

anonymous · Answer

How do I do the inverse of operations?

jumperman · Answer

That's a great question. Sometimes it helps with just taking some parts of the equation, not all parts, but some and just reversing the sign. Instead of subtracting you add. Other times depending on what type of equation it is, you have to be careful what you change.

jumperman · Answer

But inverse of operations is Sadmep. Subtract, add, divide, multiply, exponents and the parentheses. It's the opposite of Pemdas.

anonymous · Answer

Okay so what do I need to do?

jumperman · Answer

Well, I think, if this is the right type of equation is that x will always equal one, when there is no number attached to it. so I think start there.

jumperman · Answer

Then try and change the signs after that? It depends ultimately on which ones you need to change.

eric_d · Answer

6+2y=6+2y
2y-2y=0
0y=0
No solution!
am I rite @mathmale

anonymous · Answer

There had to be a solution

mathmale · Answer

This whole discussion is about solving a system of linear equations.  This means finding a point (x,y) that satisfies BOTH of the given equations.

Someone suggested using the method of elimination by substitution.  That is why he/she has suggested taking one of the two given equations and solving it for y algebraically.  If we take the first given equation, x-2y=6, and "solve for x," here are the steps of that procedure:  

x-2y=6             Isolate the -2y term by subtracting x from both sides of this equation.

mathmale · Answer

That results in

-2y=6-x

We want y alone, not -2y, so we divide both sides of the above equation by -2 to obtain

y=(6-x)/(-2)

mathmale · Answer

We can now substitute (6-x)/(-2) for ' y ' in the second equation given.

This second equation is 

3x-6y=18.

Rewrite this as

3x-6(         y           )=18.

Now you have a formula for y.  Substitute the right side of that formula inside the parentheses shown above; that is, substitute (6-x)/(-2) for y in the above equation.  

Please type out the result.