Simultaneous Equations....?

Question

Hey, I've got all my sums right, I'm just stuck on this one, it's format is completely different than the rest of the sums and it's boggling my mind...
x=3+4y
y=2+3x

If you don't want to just give me the answer then thats fine, could someone just explain how to do it please, much appreciated!

I'm off for a while, but I'll be back on yahoo answers in about half an hor to an hour, while I try to figure out the rest of these damn sums...!!

Answer 1

if you're asking for the values of x and y:

we substitute the value of x from the first equation to the second equation...

x=3+4y
y=2+3x


y=2+[3(3+4y)]

y = 2 + (9 + 12y)

y = 11 + 12y

therefore

y - 12y = 11

-11y = 11

y = -1


now we substitute the value of y to the first equation

x=3+4y ; where y = -1

x=3+4(-1)

x = 3 -4

x = -1

Answer 2

You need to get all the x and y values on the same side.
x=3+4y turns into x-4y=-3. y=2+3x turns into -3x+y=2, then just solve them the usual way. Alternately, you can use substitution since both x and y are explicitly stated. You can solve the first equation by substituting 2=3x for y from the second equation, resulting in x=3+4(2+3x) and then doing the same thing for second equation, y=2+3(3+4y).

Answer 3

It's pretty straight forward - take the first equation

x = 3 + 4y and substitue it for x in the second

y = 2 + 3x = 2+3*(3+4y) = 2+9+12y ---> now solve for y

-11 = 11y ---> y = -1

then x = 3 + 4y = -1

Answer 4

Substitute the first guy in the second guy.

y = 2 + 3(3 + 4y)
y = 2 + 9 + 12y
-11y = 11
y = -1

So x = 3 + 4(-1) = -1

Answer 5

1) rearrange one or both equations.

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

3) multiply the top equation(all terms) by -4, and this will eliminate the y term. Solve for x, then substitute back in to find y.