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SAT Math: Changing Radicals into a Solvable Quadratic Equation 0 Views
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Description:
What value(s) of x satisfy the above equation?
Transcript
- 00:00
Yeah Whoa Okay I see T mash bumpers on the
- 00:05
radical problem for you You got a growed to expose
- 00:08
Five is x minus four Question what value of X
- 00:13
satisfy the above equation So what excuse do we have
- 00:17
here All right well this is one radical equation It's
Full Transcript
- 00:20
all about overthrowing modern society And having everyone make a
- 00:23
living is a butter churn Er what can we do
- 00:25
to change this radical into something a little more civilization
- 00:28
friendly Well square both sides of the equation for one
- 00:31
So let's just go do that thing And we've got
- 00:34
then to X minus five is the quantity x minus
- 00:37
four squared What Looks like we have a much less
- 00:39
anti social quadratic on our hands Now multiply out the
- 00:42
term on the right and then gather all the light
- 00:45
terms on one side of equations that gets us Was
- 00:48
that X square than minus Its foreign minus eight Acts
- 00:52
plus 4 square 16 Then we had to explain it's
- 00:54
five over here So let's just get that over here
- 00:57
Two zeros we're gonna add five there gets twenty one
- 00:59
then we're going to subtract two x here so it
- 01:02
gets is already on the ten X ofthe equation is
- 01:04
X squared minus ten x plus twenty one Oh I
- 01:07
see A three and seven Our future Now it's factoring
- 01:10
time So what is it while X minus three and
- 01:12
X minus seven right Well the solutions to this quadratic
- 01:15
equation are X equals three and seven rights Opposite sign
- 01:19
there That was negative SARS or positive which isn't the
- 01:22
correct answer See they would've fooled you with tea there
- 01:25
We don't want the solutions to this quadratic equation We
- 01:28
want the solutions to the radical equation we started with
- 01:32
So we have to plug in three to the original
- 01:34
equation though and no dear things go awry How so
- 01:38
While we get two times three that's six months five
- 01:41
is three months for a square root of one is
- 01:44
negative Once a one equals negative one How can that
- 01:47
be Yeah taking the square root of something I won't
- 01:50
ever give us a negative number So our only solution
- 01:53
is X equal seven So you've got to get rid
- 01:55
of the native one Just keeping a really well
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