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 Originally Posted by seven-deuce
Does anyone know any websites that will teach you how to move stuff around/manipulate the equation to find what you want? I' m comfortable mixing numbers and letters but i don't know what you can or cannot do to an equation and how to break it down
Properties_of_Algebra
 Originally Posted by seven-deuce
all i remember from school is if something crosses the equals sign it does the opposite but when iv been trying to figure out some of spoons algebra before this didn't even apply
Better to think of it as: anything you do to one side of the equals sign, you do to the other side as well.
E.g. 2x + 1 = 5
subtract 1 from both sides
2x + 1 - 1 = 5 - 1
simplify
2x = 4
divide both sides by 2
2x/2 = 4/2
simplify
(2/2)x = 2
(1)x = 2
x =2
 Originally Posted by seven-deuce
example of where i get stuck;
B/(B+F) = 0.27
B = 0.27(B+F) so to get this far we take the (B+F) over the '=' sign and it comes multiply as it was divide the other side? Is that right?
Use my prior method.
B/(B+F) = 0.27
multiply both sides by (B+F)
B/(B+F) x (B+F) = 0.27(B+F)
simplify
B x (B+F)/(B+F) = 0.27(B+F)
B x (1) = 0.27(B+F)
B = 0.27(B+F)
 Originally Posted by seven-deuce
B = 0.27B + 0.27F then we multiply out the brackets to get this line
Yes, you applied the distributive property, which is the next step.
B = 0.27B + 0.27F
Then, we're solving for B, so we want all of the B's by themselves on one side of the equation... so we subtract 0.27B from both sides.
B - 0.27B = 0.27B + 0.27F - 0.27B
simplify
B - 0.27B = (0.27B - 0.27B) + 0.27F
B - 0.27B = 0.27F
now use the distributive property in reverse
(1)B - 0.27B = 0.27F <-- just showing the hidden 1 that multiplies, well everything.
(1 - 0.27)B = 0.27F
simplify
0.73B = 0.27F
Now, if we solve for B, we divide both sides by 0.73
0.73B/0.73 = 0.27F/0.73
simplify
(0.73/0.73)B = (0.27/0.73)F
(1)B = (0.37)F
B = 0.37F
EDIT link to hyperphysics
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