Question

If 21b+5=15b+9, then the value of ‘b’ is 1)-2/3 2)3/2 3)2/3 4)-3/2​

Answer 1

Answer:

3) 2/3

Step-by-step explanation:

For finding b,

21b + 5 = 15b + 9

(group to like factors, by changing it to LHS and RHS and sign change too)

21b - 15b = 9 - 5

          6b = 4

           b = 4/6 (common factor as 2)

              = 2/3

Therefore the value of b = 2/3

Answer 2

Answer:

The correct answer is an option ( 3 ) $\frac{2}{3}$

Step-by-step explanation:

In context to the question asked,  

We have to find the value of b,

As per data given in the question,  

It is given that,

$21b+5=15b+9$

Here, we have to use the transposition method:

Now, subtract $5$ on both sides:

=> $21b+5-5=15b+9-5$

=> $21b = 15b +9-5$

Subtract the numbers,

=> $21b = 15b +4$

Subtract $15b$ on both sides:

=> $21b-15b = 15b +4-15b$

=> $6b = 4$

Divide both sides by $6$,

=> $b = \frac{4}{6}$

Now, canceling the terms:

=> $b = \frac{2}{3}$

Hence, the value of b is $\frac{2}{3}$.