Question

Please help!!! =(

Elimination method

3x + 2y= 9
6x + 5y= 15

Answer 1

please tell me why i have to multiply it by 2

Answer 2

If you multiply both sides of the first equation by 2, the coefficient of x will become the same as the coefficient of x in the second equation. Then, by subtracting the equations, the term in x will be eliminated and you can solve to find the value of y.

Answer 3

i really dont understand y it has to be multiplied by 2

Answer 4

where does the 2 come from and can it be a number other than 2

Answer 5

We want the term in x in the first equation to become equal to the term in x in the second equation.
So, what do we need to multiply 3x by to make it equal to 6x?

Answer 6

how would it be equal to the second equation.......

Answer 7

4y does not equal to 5y

Answer 8

No, we are not trying to make the first equation equal to the second equation. We want to make the terms in x the same in both equations.

Answer 9

im still confused...

Answer 10

Can I repeat my earlier question:
We want the term in x in the first equation to become equal to the term in x in the second equation. So, what do we need to multiply 3x by to make it equal to 6x?

Answer 11

2

Answer 12

Correct! So now we need to multiply all the terms in the first equation by 2, giving:
6x + 4y = 18 ...........(1)
Now if we subtract the second equation from equation (1) we get:
6x + 4y -(6x + 5y) = 18 - 15 ........(2)
Now can you simplify equation (2) to form a new equation with the terms in x eliminated?

Answer 13

okay i still dont understand why it has to be 2..........

Answer 14

We have chosen 2 as the multiplier for the first equation to get the result in equation (2) above, where the terms in x will be eliminated.

Answer 15

If we had chosen a different multiplier, say 5, then we would not have been able to eliminate the terms in x simply by subtracting one equation from another.