Can someone explain y-intercept? i had a test, and i am pretty sure i bombed it. i really need

Y-intercept, it can be described as y-intercept form, or another way of writing it in mathematical form is y=mx+b, this can be used to draw polygons, find ortho-centers (very difficult), etc. m is the rise/run, rise over run, or 1/2.  The rise and the run is the rate of change.  b is the starting point or slope where it starts at, that is most of it!

About Y-Intercept:

Y - intercept is part of an ordered pair. The y-intercept is the 2nd number in an ordered pair. Like, for example, (3,5)... 3 is the x - intercept & 5 is the y -intercept. Y-intercept is a point on the line & is also known as the starting point. Y - intercepts can be used in 4 different forms: Standard Form, Slope -Intercept Form, Point Slop Form, and this form (Y2 - Y1)

                                                                                   X2 - X1

Hope this info helps!!! :)

c-4 is the final answer! : )