Question

I need to write the slope-intercept equation for a line that passes through the points (-3,0) and (3,1).

y=mx+b, so using y1-y2/x1-x2 I get a slope of 1/6, changing the equation into y=1/6x+b

How do I find b?

Answer 1

or to relate it to finding slope ... we can progress thru these steps
\[\frac{y-Py}{x -Px} = m\]
\[y-Py = m(x -Px)\]
\[y-Py = mx -mPx\]
\[y = mx -mPx+Py\]
\[y = mx +[-mPx+Py]\]
\[y = mx +b\]

Answer 2

Can Py be any of the y variables in the two given points? Likewise for Px?

Answer 3

in a sense, yes; but make sure your Py and Px are from the same given point :)

Answer 4

once you know: y=mx+b, you can actually find "b" by using either given point as well.

Py = m(Px) + b
Py - mPx = b; which amounts to what i wrote above i believe