To find the y-intercept from the point-slope form of a linear equation, you can follow these steps:
- Understand point-slope form: The point-slope form is given as
y - y_1 = m(x - x_1)
, wherem
is the slope and(x_1, y_1)
is a point on the line. - Rearrange the equation: To find the y-intercept, you need to express the equation in the slope-intercept form
y = mx + b
, whereb
is the y-intercept. Start by isolatingy
:
y = m(x - x_1) + y_1
- Expand the equation: Multiply through by the slope
m
to get:
y = mx - mx_1 + y_1
- Identify the y-intercept: The y-intercept
b
is the constant term in this equation. Hence, you can express it as:
b = -mx_1 + y_1
- Conclusion: You can find the y-intercept by substituting the values of the slope
m
and the coordinates of the point(x_1, y_1)
into the equation forb
.
For example, if you have a slope of 2 and a point (3, 5), the calculation for the y-intercept would be:
b = -2(3) + 5 = -6 + 5 = -1
Thus, the y-intercept is -1.