Question

Describe the steps needed to find the y-intercept of the graph using point-slope form.

Answer 1

If we have an equation of the form:

$y-y_1=m(x-x_1)$

and we need to find the y-intercept form we have to make the multiplications in the equations.

$\begin{gathered} y-y_1=m(x-x_1) \\ y-y_1=mx-mx_1 \\ y=mx-mx_1+y_1 \end{gathered}$

Then we compare the last equation with the slope-intercept form:

$y=mx+b$

Therefore, the y-intercept of the line will we the number:

$-mx_1+y_1$