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VCE Stuff => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematics => Topic started by: chuckjefster90 on April 25, 2010, 12:17:35 pm

Title: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: chuckjefster90 on April 25, 2010, 12:17:35 pm: Hey Guys,
This is a silly question but:
Is y=7-5x
the samre as y= -5x + 7 OR y= -5x - 7 ????

Thanks
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: superflya on April 25, 2010, 12:18:49 pm: y=7-5x is the same as y=-5x+7. theres a +ve infront of the 7.
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: m@tty on April 25, 2010, 12:19:33 pm: $y=+7-5x=-5x+7$

In your alternative you have changed 7 from positive to negative.
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: vea on April 25, 2010, 02:52:06 pm: It is the same as the first option you've listed.
The other option you've listen has a y-intercept of -7 instead of 7 and you can check and see the difference by sketching the two graphs :)
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: Yitzi_K on May 01, 2010, 07:16:45 pm: Alternatively it could be written $y=-(5x-7)$
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: naved_s9994 on May 01, 2010, 07:18:14 pm: Quote from: superflya on April 25, 2010, 12:18:49 pm
y=7-5x is the same as y=-5x+7. theres a +ve infront of the 7.

sub in a value, and see if its the same :)
Title: Re: Silly Question - Just need Clarification - is y=7-5x the same as y=-5x-7
Post by: TrueTears on May 01, 2010, 07:56:18 pm: yea implied addition