this is what we call the peel the onion
strategy so on a problem like this what
we simply need to do is isolate the X it
seems fairly basic on this but there's a
lot that's happening to this x right we
have it multiplied by two here
subtracted by four here and then we have
the square root of it then it's being
multiplied by two and then it's be
subtracted by four so to go ahead and
solve for x we need to understand how to
approach this what we're looking for
well when we have a function like a
square root or a power or a fraction or
a rational function or s or cosine or
any whatever logarithm whatever the
function may be there's an inside and an
outside of that function for the square
root or a radical anything that's under
that radical is going to be what we call
inside of our function so what we're
going to want to do focus on first is to
isolate that function so right again the
square root function is going to be our
function we need to isolate it so what
that means is we need to undo the two
and the four so which one do we choose
because a lot of students will make the
mistake they'll start reducing these
with the X because these are directly
impacting the ax and no if you think
about an onion right the onion has many
layers inside of it and what we want to
do is we want to work from the outside
all the way in so in this middle here's
we have the nice little X all right so
what we're going to do is we're going to
work on this outside and these are going
to be like your operations so the first
operation that we always want to be able
to do is anything that we have addition
or subtraction okay so you can see the
first devil here is we have subtraction
of 4 so the first thing I'm going to do
is add a four to both sides so 5 = a 2 <
TK of 2 x - 4 then the next layer is
going to be multiplication or division
we want to see is there anything
multiplying or dividing by our function
well in this case we have a two so we're
going to go and divide by two on both
sides again notice that's two times this
function the square root of 2x - 2 so
those are only going to divide out so
now I'm left with a 5 Hales is equal to
a < TK of a 2x - 4 now we have obtained
now what we've done is we've isolated
our
function okay and actually we have one
more here so we've isolated the function
now what we need to do is understand
what is the inverse operation of our
function right logarithm exponential we
could have a a fraction s cosine there's
many many different functions that we
can deal with well for the square root
the inverse operation is going to be to
square both sides so now Square both
sides and I'm left with a 25 over 4 = a
2x - 4 now you see I have an X right
multiply by two subtract by four so now
I'm just going to do the same thing that
I did before I'm just going to undo
addition and subtraction and then I'm
going to undo multiplication division
right we're always doing our reverse
order of operations now I ran out of
space because I was kind of writing too
big but that's okay so I always want to
add you know four on both sides and then
you're left with a 25 over four the main
thing I want you to understand is how do
you add 25 or four to a four well the
main thing you're going to want to do is
change your four into a fraction and
again to add fraction they got to be the
same denominator so if you multiply by a
4 over4 I don't know where I read a
division bar there then what that's
going to give you is a 16 over4 so now
what I have is a 2X is equal to a 16
over 4 plus a 25 over 4 well 16 + 25 is
going to be a 41 so 2x is equal to a 41
over 4 now I can undo my multiplication
by dividing by two and remember dividing
by two is the same thing as multiplying
by 1/2 right so therefore I have an X is
going to equal to a what was it
41 over 8 hopefully this video was
helpful for you if it was then check out
the next video I have for you here