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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

Question 6 Linear Equations in One Variable - Exercise

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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