Question

elimination or Addition
1/2x+2/3y=1
1/4x-1/5y=-1/10

Answer 1

What do you get post it here..

Answer 2

@waterineyes I was confuse in messages. Lol my y=3/4

Answer 3

y=6/8?

Answer 4

Multiply first equation with 6 and second with 20

you will get:

3x + 4y = 6

5x - 4y = -2

Right??

Answer 5

so I am going to use the equation where i use my LCM?

Answer 6

Now just add them;

8x = 4

x = 1/2

Now put this value in any one equation:

3x + 4y = 6


Subtract 3x both the sides:

4y = 6-3x

4y = 6 - 3/2

4y = 9/2

y = 9/8

Answer 7

ok. Thanks. I though i need to substitute x to the original equation

Answer 8

You can substitute anywhere result will be the same..

Answer 9

thanks @waterineyes becausei use 1/2(1/20+2/3y=1

Answer 10

Suppose now I plug the values of x in second equation:

5x - 4y = -2

Subtract 5x:

-4y = -2 - 5x

-4y = -2 - 5/2

-4y = -9/2

multiply -1 both the sides:

4y = 9/2

y = 9/8..

Answer 11

becausei use 1/2(1/2)+2/3y=1

Answer 12

i go back to the first equation

Answer 13

There you will have to use LCM and the solution becomes lengthy..

So you should put the calculated value in the expression which is easy to solve.

Answer 14

thanks a lot again

Answer 15

Welcome dear \(\huge \color{green} {\checkmark}\)

Answer 16

the link that I read they always go back to the first equation though http://www.purplemath.com/modules/systlin5.htm

Answer 17

In this case if we use very first equation then we have to take LCD and then we have to solve it becomes lengthy..

No doubt if your question is directly like this:

3x + 2y = 15
4x + 7y = 20

find x and y..

Here first you will find x and after that you will put it directly in first because this one is different from that fracitoned equation 1/2x + 1/2 y whatever it is..

So, try to keep things simple but not simpler..

Answer 18

thanks again @waterineyes

Answer 19

Welcome..

and you can note this point that all the equations given in that link are simple like:

x + y = 2
3x + 3y = 6

Like this..


Am I right??

Answer 20

yeah

Answer 21

Take care @nia_maepenix

Answer 22

thanks for the help dear @waterineyes

Answer 23

Happy To Help..

Welcome dear.. \(\huge \smile\)