Determine whether the formula describes y as a function of x. Explain your reasoning. y = 9x + 1

Question

Determine whether the formula describes y as a function of x. Explain your reasoning.  y = 9x + 1

mertsj · Answer

Do you know what the graph looks like?

anonymous · Answer

yes

mertsj · Answer

Do it pass the vertical line test?

mertsj · Answer

Does it , I mean

mertsj · Answer

Can you draw any vertical line that crosses it more than once?

anonymous · Answer

no?

mertsj · Answer

So it passes the vertical line test and it is a function.

anonymous · Answer

stupid question but what exactly is the vertical line test?

mertsj · Answer

Also it says y =   and the other variable is x so it does express y as a function of x

mertsj · Answer

In a function, none of the ordered pairs can have the same x value.  Do you know that?

anonymous · Answer

yes.

mertsj · Answer

If two ordered pairs do have the same first number, one is below the other...in other words, if you connected them, they would make a vertical line.

mertsj · Answer

So if you have a graph that had two points that would make a vertical line, it cannot be a function.

mertsj · Answer

Example:
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mertsj · Answer

Not a function. It flunks the vertical line test.  There are many pairs of points that have the same first number.

mertsj · Answer

|dw:1367287633352:dw|