The y – intercept formula is used to the find the point where the graph of a line touches the y – axis. For a line having the equation in the form Ax+ By = C, the y–intercept formula is y = C / B. If the equation of a line is given as y = mx + b, then the y – intercept formula for it is y = b.
Example 1: Find the y – intercept of a line represented by the equation given below:
5 x + 9 y = 3
Solution: The given equation of line is 5x + 9y = 3. By comparing it with the equation Ax+ By = C, we can find the values of A, B, C.
Thus on comparison we get A = 5, B = 9, C = 3.
The y – intercept formula for this form of equation is y = C / B.
Putting the values of B and C, we get
y = 3/9
y = 1/3
Therefore the y – intercept for the given equation is (0, 1/3).
Example 2: Find the y – intercept for the equation y = - 3x + 10.
Solution: The given equation is of the form y = mx + b. By comparing the given equation with the standard
form of equation, we can find the values of m and b.
On comparing we get, m = -3, b = 10
The y – intercept formula for this form of equation is y = b.
Thus y = 10
Hence the y – intercept for the given equation is (0 , 10).