Literal Equations

[Dillinger4]

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. 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. 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.

[wy125]

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.

[Dillinger4]

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).