Question

What should be the first step in adding these equations to eliminate y?

3x + 4y = 8
+ 6x – 2y = 9

A. Multiply the top equation by 6.
B. Multiply the top equation by 2.
C. Multiply the bottom equation by 2.
D. Multiply the bottom equation by 3

Answer 1

C. Multiply the bottom equation by 2

Answer 2

(C) Multiply the bottom equation by 2.

Explanation:

The given equation are:

`3x+4y=8` (1)

and
`6x-2y=9` (2)

Now, in order to add these equations and eliminate y, we should multiply the bottom equation by 2, thus we have

`3x+4y=8` (3)

`12x-4y=18` (4)

Now, adding the above equations, we have

`15x=26`

`x=(26)/(15)`

Now, substituting the value of x in equation (3), we have

`3((26)/(15))+4y=8`

`y=(7)/(10)`

Therefore, option (C) is correct.