Perpendicular Lines

[paulxzt]

Can someone help me with this ? I got a review packet for break but I seemed to have forgotten how to do this:

The value of k for which the line 3x+ky-5=0 is perpendicular to the line x - 2y + 7 = 0 is ?

I set them in slope form

y = [ -3x + 5 ] / k and y = [ x + 7 ] / 2

do I set the slopes so their product is equal to -1? Thanks for any help

 

[tkhunny]

Slope Form? What is that?

The slopes are -3/k and 1/2. Indeed, their product is -1.

 

[Ash3024]

The form he is referring to is Slope-Intercept Form Which is:

y=mx+b

Where Y is the dependent variable; x is the independent variable; m is the slope of the line; and b is the y-intercept.

 

[tkhunny]

Thanks for that nice guess. You may be right, or not. Only the student knows for sure.

 

[Ash3024]

Tkhunny:

I'm not sure if I'm supposed to be or not, but I'm sorry if I offended you in the last post that I had left.

Slope Form? What is that?

The slopes are -3/k and 1/2. Indeed, their product is -1.

Assuming that you asked what slope form was, I figured you did not know what it was. Thus, I explained what slope-intercept form is.

Thanks for that nice guess. You may be right, or not. Only the student knows for sure.

And considering the last post you left, seems like it was a sarcastic kind of 'thank you,' I figured I must have missed your intentions of making the 'student' explain himself or think through; or You think my answer was wrong. And it is not.

So, again I say, I'm sorry if I offended. Good Day.

 

[stapel]

I figured you did not know what [slope form] was.

I could be mistaken, but it seems to me that the point of the tutor's gentle question was that there is no "slope form". There is, however, a "slope-intercept form" and a "point-slope form".

You made a guess as to which of these two the poster meant. As the tutor pointed out, your guess is just that: a guess. Only the student knows which form the instructions specified.

Many tutors have learned from experience that presuming to know a student's intended meaning frequently backfires. Hence, the request for clarification.

Thank you for your understanding.

Eliz.