The following linear functions are perpendicular lines. 3y=9x-12 and -x-3y=-21

Question

anonymous · Answer

true or FALSE?

mertsj · Answer

What is the slope of 3y=9x-12?

anonymous · Answer

9?

anonymous · Answer

im guessing...

mertsj · Answer

It needs to say y= something.  Then the coefficient of x will be the slope.  So divide both sides by 3 to get it into the y = mx+b form

mertsj · Answer

What did you get?

anonymous · Answer

Slope of 3y=9x-12 is 3
Slope of -x-3y=-21 is -1/3, when multiplying 3 and -1/3 we get -1 which is a characteristic of perpendicular lines.

anonymous · Answer

OHHHHHHHHHHHHHHH, :) soo it's TRUE..

mertsj · Answer

So yes;.  Lots of people could have told you that it is true.  And now you still don't know how to do the problem yourself.

anonymous · Answer

yea i do, u just explained it 2 me

mertsj · Answer

Understanding what someone else did and doing it yourself are two completely different things.