Math Is Fun Forum

x = 0
y = 0

I thought I had to multiply it.

Is this the equation 0 + 7y = 23?

x = 12
y = 48

4x + 4y = 8 ?

I'm getting kinda confused now..

I don't see any other way to make the variables line up besides making the second equation x + 2y = y and I'm not sure if that is even legal in math.

Wait, are we doing the same thing? I was just trying to line up the x's and  y's..

Wait, wrong numbers

here's step 1 for 12:

12.  4x + 3y = -15
       y = x + 2

Becomes

3y + 4x = -15
y =  x + 2

y = 2

I got 1.

All I understand about this type of problem is that;
Step 1. Line up the x's on top of each other, the y's on top of each other, and the the equals signs and the numbers on top of each other.
Step 2. Multiply the equations (if necessary) so that we have a variable with the same coefficient

Besides that I don't understand this.

You said, "The amount of 'y' is the same in both equations,  so you can eliminate y by subtracting terms.

(x-3x) + (y -y) = 0 - -4"

My question is how do I know whether I'm supposed to subtract or add on that step?