last last question...im sorry if your annoyed already.... how did you get 4X in 4X = 1000 is it because the 3X = Y and Y represents 1? and just add it to 3x so it will be 4x? am i right?
the second equation tells you what y is, so put it into the first one
x + 3 x = 1000
and x = 1 x so you have
1 x + 3 x = 1000
and by a property of addition and multiplication called distributivity
(1 + 3) x = 1000
so
4 x = 1000
then divide both sides by 4
x = 250
and from the equation
x + y = 1000
substitute the value of x
250 + y = 1000
subtract 250 from both sides
y = 750
(you could use the other equation to find y:
3 x = y
substitute x
3 250 = y
evaluate 3 250
750 = y
)
This is good practice for my algebra, we have to do stuff like this, and explain why we can do every single step from the basic properties of the number system (or other more abstract systems). I got my library card today so next week I'll be going there every day to learn algebra :-)