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lcraig22
Nov 4, 2009, 10:47 AM
To find the x and y intercept of an equation must I first put it in y=mx+b format?

Gernald
Nov 4, 2009, 10:49 AM
you don't have to for all equations; but it helps.

itsamor
Nov 4, 2009, 10:52 AM
look at this
x-Intercepts and y-Intercepts (http://cs.selu.edu/~rbyrd/math/intercept/)

also googling your question you'll probably find a quicker solution =]

Nhatkiem
Nov 4, 2009, 12:02 PM
To find the x and y intercept of an equation must I first put it in y=mx+b format?

What the format y=mx+b (this is known as the y-intercept form) allows you to do is get information quickly by plugging in a value for x you get an output for y. Similarly you can write that x=\frac{y-b}{m}, now your inputs for y will give an output for x. Its all just formatting.

As for intercepts, all they are, are points along either your x or y axis. Lets take a look at x intercepts.

An x intercept is when the graph crosses along the x axis. Along the x axis, your value of y is 0 regardless of the value of x! This is why when finding x intercepts you make y a value of "0", this insures that for any value of x, it will be on the x axis.

Similarly for y intercepts, it is any value of y when x is 0, because any point of y when x is 0 will be on the y axis. This is also why when finding your y intercepts, you make y a value of "0".

I hope this made sense! If it doesn't, try drawing any function on a graph that goes through the x and y axis, and write down the coordinates of those points and you'll see it more clearly.

Perito
Nov 5, 2009, 10:41 AM
To find the x and y intercept of an equation must I first put it in y=mx+b format?

I would say, "normally, yes".