Thread: Rewriting function equation

Rewrite the equation y = –2x – 4 as a function of x.

Please rtell me this is right.....

y + 4 = -2x

Originally Posted by Patience

Rewrite the equation y = –2x – 4 as a function of x.

Please rtell me this is right.....

y + 4 = -2x

not completely. a function of x means we want x ONLY on one side of the equal sign.

so

y = –2x – 4
=> -2x = y + 4 ..........you were right up to here
=> x = (y + 4)/-2 ......divide both sides by -2
=> x = (-1/2)y - 2

Originally Posted by Patience

Rewrite the equation y = –2x – 4 as a function of x.

Please rtell me this is right.....

y + 4 = -2x

Writing this as a function of x would usually require something like:

y=f(x),

where f:x in R -> -2x -4

or alternatively y(x)=-2x -4.

RonL

Originally Posted by CaptainBlack

Writing this as a function of x would usually require something like:

y=f(x),

where f:x in R -> -2x -4

or alternatively y(x)=-2x -4.

RonL

well that's true, but i just figure she made a typo or phrased the question incorrectly.

afterall, what self-respecting math book would give a problem where the solution is just to add (x) on one side? seems trivial to me

Originally Posted by Jhevon

well that's true, but i just figure she made a typo or phrased the question incorrectly.

afterall, what self-respecting math book would give a problem where the solution is just to add (x) on one side? seems trivial to me

Yes, but I can't let misuse of mathematical language go without comment.

Seeing as you have already answered the question that was probably
intended it is of some importance to show that the question as asked
means something entirely different.

RonL

Originally Posted by CaptainBlack

Yes, but I can't let misuse of mathematical language go without comment.

Seeing as you have already answered the question that was probably
intended it is of some importance to show that the question as asked
means something entirely different.

RonL

agreed