Trouble with an equation?

Question

Could someone explain to me how to do this problem?

Solve for b:

1/3b - 3/4b=3

I made both denominators 12 and this is where I am stuck :

-5/12b= 3

what now?

Answer 1

best way to solve this is by multiplying whole equation by lcm of denominetors...i..e

(1/3b - 3/4b=3)*12b.....

i..e

4-9=36b

i..e b= -(5/36)...

b= -0.13888   :-)  

Answer 2

multiply both sides by 12

-5b=36

b=36/-5

b=-7.2

Answer 3

1/3b-3/4b=3

use 12 as the lcd

4b-9b=36

-5b=36

b=-36/5= - 7 1/5

Answer 4

You will need to isolate B (get B by itself on one side of the equation) To do this think about what you will need to do, multiple, divide, add, subtract, to get this done on the left side and then do it on the right side. Once you are here, you need to get the 3 on the right side to the left.

Once you have done that you will need to do the math on the number side to get your answer.

I hope that this helps you.

Answer 5

If you multiply both sides by 12 you get;

12/3b - 36/4b = 36

make the common denominator 12;

48/12b - 108/12b = 36

so -60/12b = 36

simplify;

-5b = 36

so b = -7.2

I think this is correct...

Answer 6

when solving for a variable you want b by itself

so...

you multiple -5/12 by its reciprical

so...

b= 3 * (-12/5)

so...

b= -36/5

and if you plug that answer back into the eq. it should work

: )

Answer 7

You pass b to the other side multipying, then pass 3 dividing to the other side and you get b = -5/36

Answer 8

Hi,

multiply the equation by b and it will be

1/3-3/4=3b

and solve it for b

b= (1/3-3/4)/3