Solve the inequality. Show your work. |r + 3| ≥ 7
Ok so this is greater that, do you know how to start?
No
well first, writeit two ways, greater than and less than
What does that mean?
ok well just to show you\[(r+3\ge7) or (r+3\le-7)\]
solve each of those
ok
4 or -4
close remember to subtract 3 from -7 is to add -3 to -7
10 or -10
4 or -10, you subtract 3 from both sides, do you understand or should I go back?
Please go back.
ok well first do you understand why you write it the two ways?
is it because its absolute value
right. |-5|=|5| they equal the same thing. so let's look at the first one the original. what does that look like now?
[|r+3|=|r+-3|
hold on slow down. let's look at that. I understand how you got there but let's look at it. if we plug in 5 for r, then |5+3|=|5-3| this gets us |8|=|2|. so try again. remember what the original problem is.
|r+3|=|r-3|
you're thinking about the wrong part. do you know what this will look like on a graph?|dw:1363025883735:dw| kind of like that
what was inside the absolute value bars stays the same.
OK so it should look like this |r + 3|
ok let's think about it like this. we are trying to find what r is right?
yes
so we are told that the absolute value of r plus 3 is greater that or equal to 7.
Yes
so because r is inside the absolute value bars it can be negative or positive
Would R=4?
r will be 2 things because it is in the absolute value bars. here to make it easier make the greater than or equal to an equal sign for now. |r+3|=7 what do you do first.
Minus 3 from both sides |r+3|=7 -3 -3 r=4
wait. slow down. let's just take 3 away for now. |r|=7 what is r
-7
or...
4
ok if you have |r|=7 then r= 7 and r= -7 do you understand?
Yes, I understand
so if we write it out |r|=7 and |r|=-7 so if we have |r+3|=7 how do we write it out
r ≤ -10 and r ≥ 4
just to make sure you understand so you can apply it later how do you get to that?
First I subtracted 3 from both sides |r+3|=7 -3 -3 r=4
Then I added -3+-7 And got -10 which is greater than 7
-10 which is less than 7
ok let me show you the work I did |r+3| ≥7 r+3 ≥7 r+3≤-7 r ≥4 r≤-10 plug both in to the original equation |4+3| ≥7 |-10+3| ≥7 |7| ≥7 |-7| ≥7 7 ≥7 7 ≥7 does that make sence
Yes it does make sense. Thank you so much for everything, you have been a huge help to me.
No problem any time
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