Solving Equation: trail Error method - Algebra, Mathematics, CBSE Class 6 Video Lecture

hello friends this video on algebra part
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no more fear from exam so now let's see
how do we solve these equations because
we saw that we can evaluate expressions
for me if the value of the variable is
given now when we are talking about
equations how do we solve these
equations now solving an equation what
is the meaning of solving an equation
basically so values of variables for
which left hand side is equal to right
hand side are called solutions of the
equation let's take an example so let's
say you have an equation y -2 is equal
to 4 where these are two expressions
which are equated so how do we what
would be a solution of this equation so
any value of y for which left-hand side
is equal to right hand side so what is
left-hand side in this case so here left
hand side is the algebraic expression on
the left hand side and here the right
hand side is equal to all that you have
on the right hand that is 4 so left hand
side is by -2 and right-hand side is 4
so we have to find out the value of y
for which this left hand side is equal
to write things and so let us try with
different values so let's put Y is equal
to 3 so if we put Y is equal to 3 what
is left hand side left hand side is
equal to 3 minus 2 which is 1 and what
is right hand side right hand side is 4
therefore left hand side is not equal to
right hand side ok let's try with some
other value let's put Y is equal to 4 so
if we put Y is equal to 4 then left hand
side becomes 4 minus 2 which is equal to
2 and right hand side is 4 so again at
left hand side is not equal to the right
hand side fine let's try with some other
number again so let's put Y is equal to
5 so in this case what is left hand side
it becomes 5 minus 2 that is 3 but again
right hand side is 4 so again left hand
side is not
we'll do right hand side now let's try
with another value of y let's type 6 so
this time allegiance becomes 6 minus 2
which is 4 and right hand side is also 4
so now this time LHS is equal to RHS
that means Y is equal to 6 is a solution
for this equation this is a solution for
this particular equation so not for all
equation because again Y is a variable
it will pick up different values and
different equations but for this
particular equation that is y minus 2
equals 2 for y is equal to 6 is a
solution because if you put the value of
y as 6 then the left-hand side is equal
to right hand side for this equation so
this is what we understand by solution
of an equation now how do we exactly
solve an equation so let us talk about
the trial and error method so this is
one very simple method of trying to
solve an equation however it is
important to remember that this is not a
very practical method to solve equations
I'll tell you why so for now we have
taken examples of three different
equations and we will try to solve them
by trial and error method trial and
error triangles you keep trying with
different values and you keep receiving
errors finally you arrive at that value
which is the solution for that equation
so you keep trying different different
values and you are not sure which value
will work out so that is how you
approach to solve the equation let's
look at this first equation n plus 12 is
equal to 20 so you need a value of n
such that n plus 12 is equal to 20 so
you first try with n is equal to 0 then
what happens you get LHS is equal to 12
so therefore this doesn't work because
you want left-hand side to be equal to
right hand side and right hand side is
20 so left hand side should also be
equal to 20 so n is equal to 2 0 is not
a solution let's try the N is equal to 1
so LHS becomes 13 so again 13 is not
equal to 20 so this doesn't work let's
try with N equals 2 for NHS becomes 16
which is again not equal to 20 so this
also doesn't work let's try with n is
equal to 5 so LHS becomes 17 18 that's
not equal to 20 so doesn't work let's
try the 10 is equal to 8 in that case
LHS becomes 20 and 20 is equal to right
hand side which is also 20 so therefore
n is equal to 8 is a solution for this
equation now when you look at this
approach this is a very impractical and
not a very smart approach to solve
equations because first question is you
do not know which numbers to try so you
are just trying it out of a guess you do
not know whether you should try start
trying from 0 or you should start let's
assume that if the solution for n
equation is n is equal to 56
so is it practical to check all the
numbers from 0 to 55 no that's not
practical so definitely this is not a
practical method to solve equations
however this is just the first step
where we when we are just trying to
solve an equation so let's say Q by 2 is
equal to 7 in this case also you would
see that you keep trying with many
values like u equal to 0 Q equal to 1 Q
equal to 2 and so on and none of them
work out so finally you see that Q is
equal to 14 is the value which is the
solution for this equation so again in
this case also it is not practical to
try all the values from 0 to 13 take the
third example P minus 5 is equal to plus
5 here also if you start trying from 1
to 3 and so on none of things work and
finally P is equal to 10 is the solution
for this equation so now the question is
when this is not a practical method to
solve equations so how do we practically
solve it so which is a better method to
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