y=2x
Slope intercept form:
y=mx+b
Where:
m= slope ( rise / run)
b= y-intercept (where the line crosses the y-axis)
For y= 2x, m=2 and b= 0
Graph:
For y= 4
m= 0 , b = 4
Since it has no slope, it is a horizontal line that crosses y at 4.
x= 1
It is a vertical line that crosses the x-axis at x=1