Solving for b in slope intercept form.

It's been a while since we've done this so here is a refresher:

• Find the equation of the straight line that has slope m = 4
  and passes through the point (–1, –6).

Okay, they've given me the value of the slope; in this case, m = 4. Also, in giving me a point on the line, they have given me an x-value and a y-value for this line: x = –1 and y = –6.

In the slope-intercept form of a straight line, I have y, m, x, and b. So the only thing I don't have so far is a value for is b (which gives me the y-intercept). Then all I need to do is plug in what they gave me for the slope and the x and y from this particular point, and then solve for b:

y = mx + b
(–6) = (4)(–1) + b
–6 = –4 + b
–2 = b

Then the line equation must be "y = 4x – 2"




Taken from here: http://www.purplemath.com/modules/strtlneq.htm