# the answer given in my book is 4b-3b=6+4, b= 10. but my conclusion is 4b-3b=-4+6, = -10. when do i apply positive, and when for negative?

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tx for responding to my math problem. the original problem is:-

Given the formula D/B = d+b/d-2b,

a) find B when d=1, b=3 and D=4

b) find b when B=3, D= -2 and d=2

**This is how I would do them.**

4/B = 1 + 3/1 - 2*3

Remember to do all the **multiplication** first.

4/B = 1 + 3/1 - 6**3/1 is the same as 3** so rewrite as

4/B = 1 + 3 - 6

Now do your **addition and subtraction** from left to right

4/B = -2

Undo **division with multipl**ication

4 = -2B**Undo multiplication with division**

4/(-2) = B

-2 = B because a positive divided by a negative is a negative.

Apr 23 '10

11:26 AM

For the second equation...

-2/3 = 2 + b/2 - 2*b

I would eliminate the fractions by multiplying by the common denominator , in this case 6, on both sides of the equal sign.

6(-2/3) = (2 + b/2 - 2*b)6

By doing that you have a much simpler equation to work with.

-4 = 12 + 3b - 12b

Now it is easier to combine the like terms,3b - 12b.

This will give you the equation

-4 = 12 - 9b

Subtract 12 from both sides of the equal sign.

and you have

-16/(-9) = b

simplify your negatives and you get

16/9

I hope this helps...let me know if you need more information.