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NCERT Exemplar Solutions Class 8 Mathematics Solutions for Linear Equations in One Variable - Exercise in Chapter 4 - Linear Equations in One Variable
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The value of x for which the expressions 3x – 4 and 2x + 1 become equal is
(a) -3
(b) 0
(c) 5
(d) 13/19
Answer:
(c) 5
Given, 3x – 4 = 2x + 1
Transposing -4 to RHS and it becomes 4 and 2x to LHS it becomes -2x.
3x – 2x = 1 + 4
X = 5
Video transcript
"hello students i am rita your mass
leader tutor and the today's question is
the value of
x for which the expressions 3x minus 4
and 2x plus 1
become equal so lhs
and rhs must be equal
in which of the following option 3x
minus 4 and 2x
plus 1 so one by one we put the values
and check at which point both are equal
lhs equal to rhs first a option is
minus 3 now we put the value
minus 3 in the place of x
so 3 into 3 3 9 minus 4
minus 13 now when when we solve this 2
3 the 6 plus 1 so it becomes minus 5 so
in this case
lhs is not equal to rhs
so first option is wrong now we go to
the
second option this is our a option now
b option now in b option
we again we check lhs and rhs
lhsn rhs 3x
minus 4 and 2x plus 1
we put the values we put the values
so 3 into 0
minus 4 so 3 into 0 0 minus 4
it becomes minus 4 so 2 into 0
plus 1 so 0 plus 1 is equal to
1 so again lhs does not equal to
rhs so b option is wrong
now we come to c option
in c option again lhsn
rhs
and rhs
3x minus 4
and 2x plus 1 we put the value
5 3 into 5 minus 4 so 15 minus 4
15 minus 4 it becomes 11
now 2 into 5 plus
1 to 5 10 plus 1 it becomes 11
so in this case lhs is equal to our
hs so this is our answer the c
option is the correct answer at 0.5
the value of x for both the expression
becomes
equal okay we can check also t
option we can check d
option also so the option again lhs
lhs
rhs
so lhs is 3 into
13 by 19 minus 4
and in rh is 2 into 13 by 19
plus 1 so it becomes
39 by 13 is a 39 by 19 minus 4.
and 26 by 19 plus 1
the acid is 19 so 39
minus 19 forza
76 19
26 1 19 and 19 so it becomes
19 okay now
we can minus this 76 minus 39
and 26 plus
19 so it becomes
45 by 19 and this one
16 minus 9 this becomes
7 and this is 6
so 6 minus 3 3 minus 37 by 19
so in this case lhs does not equal to
rhs it means option c
is correct and this that is our answer 5
is our answer
i hope you like this video so please
subscribe lido for more updates and do
comment your questions thank you"
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