solve for Y (2x + Y = 15)
2x + Y = 15
Y = -2x + 15
That's it! You now have an equation for a
line that intercepts the y axis at (0, 15)
and has a slope of -2.
The value of Y is variable; i.e., it changes
depending on the value of x. If you want a
specific value of Y, you must choose the
correct value of x that will give you the Y.
Plug in a few values of x and watch the
value of Y change.