Literal Equations

Right now i am trying to work with literal equations and i seem be having a hard time. I grasp the concept of some of them but other problems are just plain puzzling to me. Any help would be great. :p For instance..... I have a problem which is in the form of 2y = da which i have to solve for d. It is broken down to d = 2y / a
I don't see how this can be. If i plug any values into the variables the equation is wrong and if i assume that the variables all have a value of 1 the equation is still wrong. :confused: d = 2y / a
2 = 2 * 1 / 1.

For equations such as x + 10 = y which is x = y - 10 any values i plug in make sense. But for the previous equation i haven't a clue.

You can't plug in any values you want for all the variables that you have. In your first example, d = 2y/a, you can only have two independent variables. Once you specify these two the other one is fixed.

If you applied the same standards to the example that you say works, x = y - 10, not all values of x and y work. If you let x and y = 1 in this example the equality fails. You need to specify one and then solve for the other. That's how equations work, they tell us how the variables relate to each other.

Thanks for the help. I know that you can't plug in any values in for all of the variables. :) I understand a little better now that i took the time to look and the problem again. 20 = 2 * 10 / 2 (d = 2y / a), 2*10 = 2 * 10(2y = da).