Question

Define a variable in terms of another

Answer 1

One example is y = 2*x

The variable y is defined to be 2 times x

x and y are placeholders for a number. If you replace x with something like 9, then y = 2*x = 2*9 = 18. So x = 9 leads to y = 18.

Answer 2

If there is a particular variable you need to solve for, try to isolate that on one side of the equal sign

Explanation: