1. Here:

$-7x + \frac {27}2x + \frac 92 = -2$ ...........subtract 9/2 from both sides

$\Rightarrow -7x + \frac {27}2x = - \frac {13}2$ ...........combine the x's on the left

$\Rightarrow \frac {13}2x = - \frac {13}2$ ............divide both sides by 13/2

$\Rightarrow \boxed{x = -1}$

now continue

2. Originally Posted by Jhevon
no. that's not where you went wrong. it is the line you should have checked your answer in

you went wrong 3 lines after that. you should have subtracted 9/2 from both sides, but you did something else, i'm not even sure what
I think I divided 9/2 from -2 instead of subtracting it

3. Originally Posted by GeinoD

-7x+9y=-2
-3x+2y=1

3(-7x+9y)=-2*3
-21x+27y=-6

7(-3x+2y)=1*7
-21x+14y=7

-42x+41y=1
i have no idea what you're doing here. stick with the method we had before. i gave you the solution for x already

4. Ok, I think I understand:

-3x+2y=1
+3x +3x
2y=3x+1
/2 /2 /2
y=3/2x+1/2

-7x+9(3/2x+1/2)=-2

-7x+27/2x+9/2=-2

-7x+27/2x+9/2=-2
-9/2 -9/2

-7x+27/2x=-2/1-9/2

-7x+27/2x=-4/2-9/2

-7x+27/2x=-13/2

13/2x=-13/2
13/2 13/2

x=-1

-3(-1)+2y=1
3+2y=1
-3 -3
2y=-2
2 2
y=-1

5. And to check my answer

-3(-1)+2(-1)=1
3-2=1

-7(-1)+9(-1)=-2
7-9=-2

6. Originally Posted by GeinoD

-3(-1)+2(-1)=1
3-2=1

-7(-1)+9(-1)=-2
7-9=-2
good job. that's it!

7. Oh!!! Thank you so very much, I have done 3 question now and they all check out. Thanks, I just needed to understand what I was messing up..

Thanks

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