what is the answer to the following equation? y-3x=-4 and y=2x-1

Question

mathteacher1729 · Answer

You are looking for "The intersection of two lines".

If you would like to do so algebraically:

$$2x-1=3x-4$$
Now subtract 2x from both sides
$$-1=x-4$$
Now add 4 to both sides
$$3=x$$
Now substitute x=3 into y = 2x-1
$$y=2(3)-1$$
So y=5.

You should see this by graphing as well. On your calculator: 
$$y_1=3x-4$$
$$y_2=2x-1$$

And see that they intersect at the point (3,5).

Hope this helps.

anonymous · Answer

what is the answer to the following equation? 3x+6y=0 and y=4x+9

mathteacher1729 · Answer

Mouse -- did you understand my answer to your original question?

anonymous · Answer

not really

mathteacher1729 · Answer

Mouse -- were there any parts of the answer that made sense?

anonymous · Answer

yes like the first part of it but then i got confused.

mathteacher1729 · Answer

Ok.   That's a good start! :) If you can let me know exactly where it started to get confusing... I can help you.

anonymous · Answer

its starts getting confusing when you have to substitute.

mathteacher1729 · Answer

So you understand how I got x=3?

Once we have x = 3, then we can take that value of x (which is half the answer, we're looking for an x and a y) and insert it into either of the original equations.  That lets us solve for y.

anonymous · Answer

oh. ok. i get it now. thanks

mathteacher1729 · Answer

Awesome!