Question

Find the solution to:
x=y=7
2x-4y=8

and

5x=y=9
6x=10y=2

Answer 1

There are two methods to solve Linear equation in two variable,and,are described as follows:

1) Substitution

2) Elimination

Answer 2

Which method would you prefer @ChelseaChiodos ?

Answer 3

@ChelseaChiodos Looks like you are busy :/

Answer 4

equations don't make sense

Answer 5

@ChelseaChiodos Did you try solving them up ?

Answer 6

Yes, but it's confusing. They are systems of equations.

Answer 7

no they just don't make sense, you have 2 equal signs in one line.

Answer 8

I guess you have not posted the equations correctly,

Therfore, i would like to see you correct the equations first.

Answer 9

sorry, it's a +

Answer 10

x+y=7
2x-4y=8


Right ?

Answer 11

x+y=7
2x-4y=8

and

5x+y=9
6x+10y=2

Answer 12

Lets see the first ques

x+y=7
2x-4y=8

You can actually multiply the first equation by 2 and then subtract the two equation

which will eliminate x

Go on try it :)

Answer 13

Okay, so 2x+2y=14 - 2x-4y=8 ?

Answer 14

That would eliminate the x's
and you'd be left with...
-2y=22

Answer 15

That makes y=-11

Answer 16

So now you can put this -11 in eq 1 and find x ?

Answer 17

(18,-11)

Answer 18

You can check your answers by putting these values in eq 1 and 2 and if

L.H.S=R.H.S

then your solution is correct :)

Answer 19

Thank you! :)
Now, what about the 2nd problem?

Answer 20

5x+y=9
6x+10y=2

Umm you can take value of y from equation 1 and put it in eq 2 and the solve to get x

Go on show me how you do it.

Answer 21

Well . . . what I did was
(-10) 5x+y=9

-50x-10y=-90
6x+10y=2

Eliminated the y's and I got
-44x=-88
and divided both sides by -44
I got x=22

But it didn't seem right to me :/

Answer 22

-88/-44 = 22 ,Intelligence at its best

Answer 23

So plug 22 back into the first equation...
22+y=7

Subtract 22 from both sides
y=-15

Answer 24

@ChelseaChiodos Dumb, -88/-44=2

Answer 25

OOPS. sorry. I wasn't thinking.

Answer 26

@ChelseaChiodos You need brains to do that now put this value in the 1st equation ?

Answer 27

I appreciate your help, but could you not be a jerk? I'm cooking, doing PreCalc homework, and taking care of a 6 year old all at the same time. Sorry that my brain isn't entirely focused on math.

Answer 28

Now, y=5.

Answer 29

i believe it's called positive feedback, you're working harder now aren't you?

Answer 30

@ChelseaChiodos I am sorry if i came of as rude but i do not agree with your accussation of calling me a jerk :)

So you have done it right :)

Well maths actually needs practice not attention :)

Answer 31

Thanks, and I don't believe dumb is positive feedback. but okay.
thank you very much, and I suppose you aren't really a jerk seems how you've helped me :P So, I apologize.

Answer 32

@ChelseaChiodos I just came of like that so you utilize your brains,Sorry if you felt bad :)

Answer 33

@ChelseaChiodos Your'e welcome.