whatt??? how do i figure this out????

Question

solve for x and y using elimination or substitution methods of solving systems.

this is the problem

3x+y=6
-3+4y=9

please helop me.

Answer 1

3x + y = 6
-3x + 4y = 9

Add the equations to eliminate x

3x - 3x + y + 4y = 6 + 9
5y = 15
y = 3

3x + 3 = 6
3x = 3
x = 1

Check

-3(1) + 4(3) = 9
-3 + 12 = 9
9 = 9

Answer 2

Assuming that second equation is really supposed to have -3 as you typed, and not -3x, then you can solve this for y, and then substitute the value back in to the first equation to solve for x.

If you meant to have -3x there, then you can add the two equations together to get (3x + y) + (-3x + 4y) = 6 + 9. This is 5y = 15, which you can solve for y. Then use this value to substitute back into either original equation, and solve the result for x.

Answer 3

I'm assuming the second equation is -3x + 4y = 9. If so, you can add the two equations together as follows:

3x + y = 6
-3x + 4y = 9
-----------------
5y = 15.
y = 3.

You can then substitute 3 in for y in either equation. So if we do this in the top equation, you get:

3x + 3 = 6.
3x = 3.
x = 1.

Answer 4

First: since both equations have 3x, just add the equations.

3x + y = 6
+ -3x + 4y = 9
------------------
5y = 15

SEc: solve for "y" by isolating it - divide both sides by 5 (when you move a term to the opposite side, always use the opposite sign).

5y/5 = 15/5
y = 15/5
y = 3

Third: substitute "3" with "y" in either equation - let's use equation (1).

3x + y = 6
3x + 3 = 6 (subtract 3 from both sides).
3x+3-3 = 6-3
3x = 6-3
3x = 3 (divide both sides by 3).
3x/3 = 3/3
x = 3/3
x = 1

Solution: (1, 3)

Answer 5

From the second equation we get 4y = 12 so y =3
Thus 3x+3 =6 so 3x = 3 and x =1

If you meant;
3x+y=6
-3x+4y=9 , then just add them getting
5y = 15 --> y =3
So again x =1

So it didn't make any difference which you meant.