I'm thinking this is what the problem looks like:

. The first thing to do is to move the

over to the other side because it has a common denominator with the other side. Doing that and at the same time combining them over their common denominator looks like this:

. The best way to solve for x now is to cross-multiply to get 3(4-x)=-4(x-4). Distributing through the parenthesis is 12 - 3x = -4x + 16. Solving for x gives us x = 4. Of course when we sub a 4 back in for x we get real problems, don't we? Dividing by zero breaks every rule in math that there ever was! So, yes, the solution is extraneous.
3/5*3/3=9/15
1/3*5/5=5/15
15 is a common denominator.
Ok so...
You want to move the decimal point to the right until the number is greater than 1 but less than 10.
The number will end up being 5.2
You moved the decimal point 3 times to the right.
So it will be 5.2 x 10^-3. It is negative because you moved it to the right. The exponent would be positive if you moved it to the left
BD=10 because it is symmetrical to AD.
Answer:
12.47, 12.075, 11 1/4, 11, -12, -12.004, -12.01