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Posted by Brad Paul on October 06, 2002 at 19:18:51:

: can u please solve this c/3 + 2 is less than equal to c/5 + 1 whats the answer!!?? its drivin me nuts

Jen,

Please excuse the other response. There have been some fools
responding with other peoples names.

I imagine your question is solve for c. Let me rewrite the equation:

c/3+2<=c/5+1

This problem is almost identical to solving for c with an equal
sign. The only difference is when we multiply or divide by a negative
number we need to flip the "<" or ">" symbol. Let me give a simple
numerical example. We know the following is true:

-3<4 <- true

Now lets multiply by -1 on each side and see what we get.

3<-4 <- not true

This is no longer true. To make it true we must flip the "<" to a ">"
which will give us the correct result:

3>-4 <- true

Now when we work with an equation that has variables in it we must be
very careful to flip the "<" or ">" when we multiply or divide by a
negative quantity.

Now let's do you question:

Move the terms with the c to one side and the free numbers to the other side:

c/3-c/5<=1-2

(5 c)/15- (3 c)/15 <= -1

(2 c)/15 <= -1

(2 c) <= -15

c <= -15/2

In this case we never had to worry about the flipping of the "<" or ">" sign.

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