Y Intercept is the point where a line or curve crosses the y-axis of a graph or in other words where x=0.
Knowledge of the y-intercept can be used when graphing lines or when writing an equation in slope-intercept form.
Formula to calculate y-intercept.
We get the y-intercept by using the equation of a straight line which is;
y = mx + b
Where;
m is the gradient of the slope
b is the y-intercept.
We can use the following formula to calculate the y-intercept.
y – a = m ( x – b )
a and b being a point on a line.
Example:
Suppose you have a straight line whose gradient is 3 and a point 2,1, calculate its y-intercept.
Since the y-intercept is when x=0, therefore;
y – 2 = 3 ( x – 1 )
y – 2 = 3x – 1
y = 3x – 1
Therefore, the number that has replaced b is -1, which means that -1 is the y-intercept.