0:03 the fastest way to solve this problem on
0:04 the ged
0:07 when you have an x squared and an equal sign
0:08 sign
0:10 is to use the calculator
0:12 because there's a button on there called table
0:13 table
0:15 and we can type in the left side of this
0:17 equation here
0:20 so we'll start off with x squared
0:22 x is right there next to four
0:25 squared is right above it
0:27 then minus three x
0:28 x
0:30 minus four
0:32 from there you're just going to keep
0:36 hitting enter until you get to a table
0:38 we want to find out when the whole thing
0:39 is six
0:43 or when the y value is six
0:45 but if we just sneak down a little bit
0:47 when x is negative two
0:49 the whole thing is six
0:52 so therefore x is negative two is one of
0:54 our answers
0:56 now none of the other ones have a
0:59 negative two so the other answer should
1:01 just be positive five
1:04 all right well let's just double check that
1:05 that
1:08 and that does check out when x is five
1:12 the whole thing is six just like we want
1:15 so it's got to be b because those are
1:18 both of our answers there
1:19 when you have those squigglies it just
1:23 means multiple answers are correct
1:25 okay but what was going on because that
1:27 might have seemed like a bunch of black
1:28 magic there
1:30 well let's clear let's go to the home screen
1:32 screen
1:35 when you have this equation here we're
1:37 really just changing both of these x's
1:39 to the same number
1:41 so let's pretend we change both of those
1:43 x's 5 there
1:44 5 there
1:45 let's do it
1:48 so it's going to be 5 and that one's squared
1:50 squared
1:51 then minus
1:53 when you have a number and a letter next
1:56 to each other they're just multiplied
1:59 so we'll do three times same x value of five
2:01 five
2:03 end it with a minus four
2:06 and that gets us six
2:09 so that's why that value worked
2:11 and if we plugged in negative 2 for that
2:13 x and that x
2:16 that would also get us positive 6.
2:18 so that's what's really going on behind
2:20 the scenes
2:23 the amazing thing is the table button
2:25 just went ahead and plugged in all of
2:28 these all at once so saved us a lot of
2:31 time there
2:33 okay here's another example if you want
2:40 and let's jump into it so fastest way
2:43 when we see an x squared and an equal sign
2:44 sign
2:45 use that table
2:47 we'll clear
2:48 and let's do it
2:51 x squared minus two x
2:53 minus three
2:55 enter five times
2:57 but this time we're looking when the
3:01 solution is zero or the y value is zero
3:04 but lucky for us right away we notice oh
3:08 when x is three the whole thing is zero so
3:08 so
3:11 that one must be an answer
3:12 but once again
3:14 none of the other ones have positive
3:16 three so it looks like x is negative one
3:18 is the other answer
3:20 we'll go up to get to the negatives there
3:21 there
3:24 and sure enough x is negative one that
3:25 also works
3:29 so a those are both of our answers
3:32 okay so we could solve these all day but
3:35 what's the application here
3:37 when you have an x squared and you graph
3:41 it it's actually a smiley face
3:43 and it could represent the height of a
3:47 skateboarder on a half pipe over time
3:50 or if you have a negative x squared
3:52 that's just a frown
3:54 so that could represent the height of a
3:58 football or soccer ball being kicked
3:59 reaches a peak
4:02 comes back down hits the ground
4:06 but notice we set ours equal to zero
4:08 that's the same thing as finding out
4:10 when the height is zero
4:13 or how long it took before it hit the ground
4:14 ground
4:18 our answers are both how long it took
4:21 but negative time doesn't make sense so
4:23 we'll ignore that one
4:25 but it took three seconds after we
4:29 kicked it four the height to be zero and
4:31 hit the ground
4:33 so that's how you could use those guys there
4:38 okay here's another one
4:39 even if there's a number in front of x
4:43 squared no worries same thing
4:44 so let's do it
4:46 table clear 3
4:47 3
4:49 x squared
4:51 minus 4x enter
4:53 enter
4:57 and we're on the hunt for when y is 20.
5:00 okay let's scroll down
5:03 but no we're not seeing it there let's
5:05 go back up
5:06 and there we go
5:08 when x is negative 2 the whole thing is
5:13 20. so answer there should be d
5:15 now we could always double check it
5:17 because we could plug in negative 2 for
5:19 x there
5:22 negative 2 for x there and we could type
5:24 that in
5:27 when you replace a letter with a number
5:29 then just put it in parentheses
5:32 and then that'll work correctly
5:33 that all should give us 20.
5:36 20.
5:39 and then there's one last example here
5:41 okay this one looks a little extra but
5:45 no worries still the same process here
5:47 the only issue is when we get to the
5:49 fractions but we'll address that when we
5:50 get there
5:52 okay let's start it off
5:57 so table clear this one has a 3x squared
5:59 plus 13x
6:02 minus 10
6:04 enter five times
6:07 the only issue with the table is it only
6:09 tells you whole numbers
6:12 so we can only check whether five and
6:13 negative five work
6:15 but that's fine let's check positive
6:18 five let's scroll down
6:21 okay but that gets us 130.
6:24 we want it to be zero so it's definitely
6:26 not that one
6:28 but let's go ahead and check negative
6:30 five here let's scroll up to get to the negatives
6:32 negatives
6:34 and there we go that does work
6:37 x is negative five the whole thing is zero
6:38 zero
6:40 so that one's good
6:43 now when we're trying to check fractions
6:45 we could still do table
6:48 type it in just like we have but then
6:50 hit enter once
6:52 because we're going to scroll down
6:55 switch it from auto to ask
6:58 this allows us to plug in any x value we want
6:59 want
7:02 two thirds for instance okay so we'll
7:04 hit that
7:07 and let's do it so we'll hit 2
7:09 fraction 3
7:13 that'll plug in x is 2 3 for that x and
7:14 that x and
7:15 and
7:19 that does surprisingly give us zero
7:21 so that answer works
7:24 but we already have our two answers so
7:25 we know what those are
7:28 okay but let's just check negative
7:30 two-thirds just to make sure that that
7:32 doesn't work
7:35 and no it gives us some negative so no good
7:36 good
7:38 so let's get rid of that
7:41 okay so x is negative five was one answer
7:42 answer
7:45 positive two-thirds the other answer
7:47 and that's it
7:50 you'll be able to solve any quadratic or
7:53 x-squared problem on the ged using this method
7:55 method
7:57 you got these let me know what questions
7:59 you have but good luck
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