This video related talk about a method for how to solve systems of equations using something
called a substitution method so this will work something like this a better lawyer equations
in your system and what we're going to do is we're going to pick one variable install for it in any of the
equations it doesn't matter which equation it doesn't matter with variable but I would
recommend trying to get easy one: by easy one?
a coefficient of one the algebra turns out to be really easy to solve for
you don't have any coefficient to divide out at the end soon enough yarmulke off for why
at some point the software why you have to divide by four and a bunch of fractions the
failure of variables have a coefficient of one go for that one but other than that it
really doesn't even matter which invariably self for it is a matter which equation you
use but in any case when she saw for that guy you take him in your Guinness substitute
him into the other equation a memorial to go through an example of just the second he
bear with us and know what to do that was can happen is instead of having equation with
two variables with 1 million different solutions you have an equation just with one variable
that are just have a single solutions of him was he saw that guy should end up with your
final answer seven for example something like this essay 3X -2 Wigle seven and 4X plus Y
equals 13 together that makes a system of equations in your world what were trying to
find is an ordered pair ask why that makes both of the equations be true so out of the
system regularly guy think I would software this probably this guy says a coefficient
of one that you can solve for why I hear you. Negative 4X +13 and then when I was referencing
here when I was talking about number two was a Guinness substitute that guy now into the
other equation the other meaning the first equation now where you substituted or noticed
this right here is a why just like what we software so we know that why is the same as
negative 4X +13 so why not take this Y out and cut and paste negative works +13 in there
and you notice in your first equation which I will write out all the details right now
you wouldn't have exes and wise he does have exits should also wear to work the two examples
here's all of exes start with this one and will finish this one out in the will do will
do another mercilessness get to it so here we start by doing the same thing I did earlier
to discover here Y equals negative 4X +13 and in this guys can go in for the Y in the
first equation to death 3X minus what I usually do is all right to Y equals seven but instead
of a why are the sleeping giant blank and then I'll say okay will why is the same as
negative 4X +13 this is a a single equation with just one variable just ask that we should
be pretty good at solving was distributed negative to have 3X plus 8X possessed minus
the negative -26 = combine like terms so 11 X equals the stake 26 and added to the right-hand
side with 33 divide both sides file 11 X equals three� Just the actually been ordered pair
ask and why so for that you can go back and use any old equation it doesn't matter all
the equations are true you can use the first the second or any of the long-range shooter
I think I'm leaning towards light is the orange Lindsay was good because they don't have any
wise but if any of the first-degree equation for this one in orange and I would always
recommend using the guy where you solved for why is that should be somewhere in your previous
work it does take that equation In your axis XXXVII -4�3+13 of the -12+13 which is one
wily one that ordered pair 31 should be the solution to the system you can check it and
I would encourage you to check it especially for a test or something just takes two seconds
ago regarding your head for strike 3�3 is 99-2�1 is seven and looks good and foreclosure
is 1212+1 wise 112 and one May 13 so it satisfied the system because it made most of the equations
teachers that's a very classic a Exercise) the one we just very very very typical of
a strong one is a little more difficult maybe you can tell me what's more difficult about
this one 5X -2 Wigle's -8 negative 3X plus 5Y equals 20 L-1's harder about that looks
pretty similar to the last example if you notice none of these have a coefficient of
one that's really unfortunate I hate that by we can still do it on this villages be
better if it had a coefficient of what the thinking I ask why
it doesn't matter I guess I just think this first Gary so solving for that X we have 5X
equals 2Y -8 at two why do the right divide the five you get 2/5 Y -8 says yes I really
have fractions yes I know this ugly not really much we know that I can't take this for X
and stick it in for X in the other equation will have -3 times axis allelic to do it sleep
the big blank plus 5Y equals 20 take that expression for X applicable to this Y -8/5
distribute yes have to deal with fractions but we can do it do it -6 why -3 -6/5 Y +20
4/5+ 5Y equals 20 less combined like terms -6005 let us write this as 25 fifths silhouette
of a common denominator -6 this +25 says something that would be 19/5 Y equals and I will take
this 20 4/5 and
subtracted to
the right to -24/5 in Colorado Scotiafloataroundinthesameequationheresomarketoutontheleftandsubtractedoverheretotherightandthenforthe20commentdenominatoroffivestraight20has100overfiveisalso20butthatwillneverdenominatoroffive100over5-24576overfivealmostdonewecanmultiplybesidefivetogetridofthefivescomebackoverheresoin19Yequals76sowhywouldbeasetforlaterbeforesowiseforandthatwealsoneedtoaskthatgoeswithittakeanyoldequationthatitdoesn'tmatterwhichwere20yearsMrs.trymaybemaybethissummerhereiswhyisfortwosystemsforce-feedfifthsbecausemymistakethisgivesuszerosothere'syourorderedhairzero,forthatwouldbeyoursolutionyoucancheckitofcourse0-8as-80+20is20CNNworksoutperfectlyfinesinceitwashopefullythey'llshouldunderstandhowtosolveasystemofequationsbysubstitutionIwasthatofallthemethodsoftriggerlinewithmethatmethodrightthereisprobablythemostcommonlyusedmethodgraphinghasalotofdownsideseliminationmethodoradditionmethodonlyworkssometimesbysubstitutionworksprettydarnnearallthetimesisaveryverypopularwayofsolvingsystemsIwouldencourageyoutocommitalotofenergytotolearningthismethodwellbecauseIthinkitwillserveyouwellandsolvingallthedifferentsystems