variables with for in them?

rjgprosk

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Feb 15, 2008
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I do not under stand how to handle this?

5x+6y = 18 for y the word for is throwing me off
 

jwpaine

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Mar 10, 2007
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Was there a word preseeding the equation? Maybe something like "solve"? :wink:
 

stapel

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rjgprosk said:
I do not under stand how to handle this?

5x+6y = 18 for y the word for is throwing me off
I will guess that you missed the lessons covering how to solve literal equations. Do you know how to solve regular one-variable linear equations? For instance, would you be able to solve 5 + 8y = 18 for y?

Thank you! :D

Eliz.
 

kasie-tutor

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Jan 20, 2008
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Dear rjgprosk,

The "for" probably means "solve for [the given letter]." Do you know what that means? Hint: You can isolate y in two algebraic steps using the inverse properties of addition then multiplication.

\(\displaystyle \clubsuit\) Kasie
 

sgtpepper

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Nov 20, 2006
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Hey, if you didn't know the "for" thing, maybe you don't know how to go about isolating "y", so here you go:

5x + 6y = 18

move 5x to the right side of the equation by subtracting it:
6y = 18 - 5x

then divide both sides by 6 to get y all by itself:
6y/6 = 18/6 - 5x/6

=

y = 3 - 5x/6 or y = 3 - (5/6)x

Here's my work:
http://tinyurl.com/yte2ol

If you have time, try "solving for 'y' " in this and see what you get:

9x + 3y = 21
 
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