What’s the equation of a line that passes through points (0, -1) and (2, 3)?

Question

e.mccormick · Answer

OK, so where did you get stuck on this?

e.mccormick · Answer

This is the line it is talking about.  The goal is to find an equation that defines it.

e.mccormick · Answer

Usually you want to do this by putting it in the form of y=mx+b.  You have a y and x, two in fact.  So what you need to find is m, the slope, and b, the y-intercept.  This one was very nice because they even gave you the y intercept.

anonymous · Answer

apply the (two point form) formula.you get {(y+1)/4}=(x/2).

anonymous · Answer

You are given two coordinates. Use those two to find the slope or the "m" in: $$y=mx+b$$.
Keep in mind which is is which so you get the correct slope.

(0, -1) and (2, 3).

Use the formula below to find the slope:
$$\frac{ Y_{2}-Y_{1} }{ X_{2}-X_{1} }$$

Now plugin the values you are given: $$\frac{ 3-(-1) }{ 2-0 }$$

Which becomes:
$$\frac{ 3+1 }{ 2-0 }$$

So your slope is: $$\frac{ 4 }{ 2 }$$ or simply 2.

Now that you have your "m" for y=mx+b, you now have y=2x+B
To find what B is, use one of the coordinates. We'll use (0,-1) in this case.

y=2x+B
-1=2(0)+B
-1=B.

There's your B, you now have found the whole equation.

y=2x-1. :)

e.mccormick · Answer

@ch3n2x Yep.  I was hoping whenever they came back the clues I left would be enough.  Don't even know how far they got on it.

anonymous · Answer

(2x-y-1=0) is the equation.