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View Full Version : Slopes,parallel and perpendicular... how do I do that?help please!


butterfly21891
Sep 19, 2006, 05:47 PM
okay I was given the linear equation 2x+4y=12 and I was asked to find:

a.)an equation in the form y=mx+b
b.)an equation of line parallel to the equation
c.)a slope perpendicular to the equation
d.)an equation of a line parallel & through the point (4,2)
e.)an equation of a line perpendicular & through the point (2,0)
f.)then graph the lines

note: I was able to figure out how to get the equation in the form of y=mx+b... but what do I do to get the rest of this finished?

dmatos
Sep 19, 2006, 07:09 PM
Do you know what the "m" and the "b" in that y=mx+b equation are? They are (respectively) the slope and the y-intercept of the line. If you were to plot the line, and measure the slope (rise/run, or delta-y/delta-x), you'd get "m". If you looked at where it crossed the y-axis, you'd get "b."

Take a second and try to figure out how the slopes of parallel and perpendicular lines to your target equation would look.

s_cianci
Sep 24, 2006, 05:23 PM
To do part b.), simply keep your value of m from a.) but use a different value for b
To do part c.), your slope is -1/m and b can be anything you want
To do part d.), plug in 4 and 2 for x and y and keep your value of m from a.) and solve to find b
To do part e.) your slope is -1/m and plug in 2 for x and 0 for y and solve for b