how do you find the y intercept (b) in the equation y=mx=b where m is the slope
The y intercept is the y-coordinate of the point where x = 0.
It is where the line "intercepts" the y-axis.
So..to find the y-intercept, plug in 0 for x and solve for y.
y = mx + b
y = m(0) + b
y = b
b is the y-intercept in this equation
