Question

25. If 2x-y-4, then 6x - 3y = ??
(a), 12
(b) 20
(c) 18​

Answer 1

Answer:

12

Explanation:

multiply the equation by 3 on both sides

Answer 2

Answer:

Explanation:

n this question, we can see that there are 2 variables, but there is no way given to find out their individual values. This means that there must be another way to derive the answer, without finding the individual values of the 2 variables.

In such questions, I like to relate the L.H.S of the first equation (2x-y) to the L.H.S of the second equation (6x-3y).

To do this we have to factorize both of them.

For the second expression (2x-y), we can see that it is already given to us in its simplest form.

For the first expression (6x-3y), there is a common factor 3, present so the factorized representation of this expression would be:

6x-3y=3 ✕ (2x-y)

now the question can be reframed as:

If 2x-y=4 then 3(2x-y)=?

Since 2x-y=4, we can replace 2x-y in 3(2x-y) with 4:

3(2x-y)=3(4).

so the answer is 3 ✕ 4 = 12.

Hence 6x-3y=12.