Posted by trudy on .
Functions are a lot like equations. In a function we look at the relationship of the variables. Does one variable depend on the other.
In a function when you see f(x) it just means "y." So we have an equation y = 2x + 3 and a function that is
f(x) = 2x + 3. When graphed, they both look like the same line.
What makes these a linear equation or a linear function? How can we tell if they are linear?

college math 116 
Trinh,
The "x" is the one make a linear function or equation. Cuz x is independent variable and we just plug it in equation to find y or f(x).
Linear equation has formula: y=ax+b
Unlike parabola: y=ax^2+bx+c and so on. 
college math 116 
tesfaye,
z=4x+3y
2x+3y<=6
3x2y<=9
x+5y<=20
x>=0,y>=0