ch3. slope intercept form .

pg. 205

slope intercept form;
y=mx+b start at the y intercept (0,b); and count off the rise and run.

standard form; Ax+By=C

find the x intercept by setting y = 0. Find the y intercept by setting x = 0. Find one additional point as check.

a). the line through (0,3) that is paralell to the line y=2x-1.
solution;
the line y=2x-1 has slope 2 and any line paralell to it has a slope 2.
The equation of the line with y intercept of (0,3) and slope 2 is y=2x+3

b). the line through (0,4) that is perpendicular to the line 2x-4y=1
solution:
First find the slope of 2x-4y=1
-4y=-2x+1
y=1/2x-1/4

point slope form:

slope formula; y2-y1/x2-x1=m

let m=2/3 (x1,y1)= (4,1) and (x2,y2)=(x,y)
y-1/x-4=2/3
y-1=2/3.(x-4) multiply each side by x-4.
the slope is 2/3

point slope form

y-y1=m(x-x1)


That is all for now.

Marie Zajac
BA in Psychology with a concentration in Rehabilitation in Counseling.