Posted by xxx on Sunday, May 3, 2009 at 5:45am.
here is an easy way to draw a graph of a straight line if you given the equation in the form y=mx+b
remember that m is the slope and b is the y-intercept and slope = rise/run
then for y = (4/5)x - 3, rise/run = 4/5
and the y-intercept is -3
1. plot the y-intercept (0,-3)
2. from there count 5 units to the right, then 4 units up, basically doing a run of 5 and a rise of 4.
join the two points, and you are done.
for the first one:
y = -2x + 5 or y = (-2,1)x + 5
plot (0,5), and from there count 1 unit to the right and then 2 units down, join the points ...
All done
near the end
<<y = -2x + 5 or y = (-2,1)x + 5 >>
should read:
y = -2x + 5 or y = (-2/1)x + 5
Thank you VERY much! You're my savior :)
just one more question.. I NOW understood how to graph equations.. but I still have to graph inequalities, which seems much more complicated from my point of view.
I've got two inequalities that I have to graph.
1. y > 2/3x-4
2. y < -2
NOTE: Number 1, where it says "y > 2/3x-4"... well under ">" there is a line/dash, as to mean that it's "greater than or equal to". I hope you understand what I mean..
thanks for your help.. :)
y ≥ (2/3)x-4
graph y = (2/3)x - 4, then shade in the region ABOVE that line
had it been
y > (2/3)x-4 the boundary is the line
y = (2/3)x - 4, so draw a dotted line instead of a solid line
in general if y > mx + b
draw a dotted line for y = mx + b and shade in the region above the line
if y < mx + b
draw a dotted line for y = mx + b and then shade in the region BELOW the line
okayyy..
what about "y < -2" ????