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jimthompson5910 (jim_thompson5910):
do you know how to graph `y = -2x - 2` ?
jimthompson5910 (jim_thompson5910):
y = -2x - 2 is a linear equation. Ie, a straight line
jimthompson5910 (jim_thompson5910):
if x = 0 for instance, then y is...
y = -2x - 2
y = -2*0 - 2 ... replace x with 0
y = 0 - 2
y = -2
so we have the point (0,-2). Do you see how I got this?
jimthompson5910 (jim_thompson5910):
now use x = 1
if x = 1, then y = ???
jimthompson5910 (jim_thompson5910):
you did it right
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jimthompson5910 (jim_thompson5910):
another point on this line is (1,-4)
jimthompson5910 (jim_thompson5910):
plot the two points (0,-2) and (1,-4). Draw a straight line through them
since we have this sign ≥, which has a line under the ">", we will make this boundary line solid
jimthompson5910 (jim_thompson5910):
yeah because of that underline
jimthompson5910 (jim_thompson5910):
IF there wasn't an underline, then it would be a dotted or dashed boundary line
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jimthompson5910 (jim_thompson5910):
type `y >= -2x-2` to mean \(\Large y \ge -2x-2\)
jimthompson5910 (jim_thompson5910):
good
jimthompson5910 (jim_thompson5910):
as for the other inequality
y + x ≥ 0 is the same as y ≥ -x (Subtract x from both sides)
jimthompson5910 (jim_thompson5910):
you'll need to graph y = -x
then shade above that solid boundary line
jimthompson5910 (jim_thompson5910):
notice how in your desmos graph, the shading is above the boundary line
because of the > symbol
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jimthompson5910 (jim_thompson5910):
do you know how to graph y = -x ?
jimthompson5910 (jim_thompson5910):
it's very similar to how we graphed y = -2x-2
jimthompson5910 (jim_thompson5910):
if x = 0, then what is y when y = -x ?
jimthompson5910 (jim_thompson5910):
so one point on it is (0,0)
jimthompson5910 (jim_thompson5910):
then if x = 1, y = ???
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jimthompson5910 (jim_thompson5910):
yep so we know the two points on it are (0,0) and (1,-1)
jimthompson5910 (jim_thompson5910):
once you have y = -x graphed, you shade above the boundary line
why above? because of the > sign. This only works if y is isolated
why is the boundary line solid? because there is an underline under the >
jimthompson5910 (jim_thompson5910):
now do both graphs at the same time
jimthompson5910 (jim_thompson5910):
very good
jimthompson5910 (jim_thompson5910):
the final step is to only shade where the two regions overlap one another
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jimthompson5910 (jim_thompson5910):
yeah pretty much
jimthompson5910 (jim_thompson5910):
yeah you follow all those steps. Using desmos, or anything like it, is a good way to check the result