SOLUTION: I'm a homeschooling mom trying to help my daughter, but this problem we just can't understand. We need to solve(find the system of equations) first by graphing and then by adding o

Algebra ->  Graphs -> SOLUTION: I'm a homeschooling mom trying to help my daughter, but this problem we just can't understand. We need to solve(find the system of equations) first by graphing and then by adding o      Log On


   

Question 53302: I'm a homeschooling mom trying to help my daughter, but this problem we just can't understand. We need to solve(find the system of equations) first by graphing and then by adding or subtracting.
The problem is:
6X-4y=28
4X+9y=-6
We first decided to make X the same so we ended up with
24X-16y=112
24x+54Y=-36
Then we isolated the 24x so we ended up with
24x=112=16y
24x=-36-54y
I think then we have to take 24 by division off from the x side,but I just can't seem to make any sense out of it.
Thanks for your help.
Tina
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The problem is:
1st: 6X-4y=28
2nd: 4X+9y=-6
We first decided to make X the same so we ended up with
3rd: 24X-16y=112
4th: 24x+54Y=-36
Now subtract 3rd from 4th to get:
70Y=-148
Divide both sides by 70 to get:
Y=-74/35
Substitute that into 1st or 2nd to solve for X, as follow:
6X-4(-74/35)=28
6X+296/35 = 28
Multiply by 35 to get:
210X+296=980
210X=684
X=114/35
Check the answer with 2nd, as follows:
4X+9Y=-6
4(114/35)+9(-74/35)=-6
-6=-6
Cheers,
Stan H.