what does the y in y=mx + b mean

Question

 i understand what mx and b is but i can never understand what the y is

Answer 1

Take the equation:  y = 3x - 4

 

This is a line with slope m=3, y-intercept -4,

meaning the graph crosses the y-axis at (0, -4).

 

The y values are the output values for a given

input value x.  The possible output values,y, make

up the range.  The possible input values, x, make

up the domain.

 

If x = 2

y = 3(2)-4 = 2

Thus the point (2,2) is on the graph of the line.