I'm trying to remember algrebra to help my 4th grade son.
If x=3 and y=3-4x, what is y?
When you have equations like this and you're given one of the variables, all you do is plug that variable value into the equation.
Here we have x=3. That means that in our equation y=3-4x, the x can be replaced with the 3 as follows:
y=3-4(3). Multiply the 4 and 3.
y=3-12. Subtract 12 form 3.