SOLUTION: 1.) 3x+y=15
y=3
2.)3x-2y=12
-y+9=x
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Question 16708: 1.) 3x+y=15
y=3
2.)3x-2y=12
-y+9=x
Answer by elima(1433) (Show Source): You can put this solution on YOUR website!
1.) 3x+y=15
y=3
This equation you are just going to plug in the y=3 into the equation;
3x+3=15
subtract 3 from both sides;
3x+3-3=15-3
3x=12
Divide each side by 3;
=
x=4
2.)3x-2y=12
-y+9=x
This equation your are first going to solve the second equation for y;
-y+9=x
y=-x+9
Now plug that into the other equation for y;
3x-2(-x+9)=12
3x+2x-18=12
Add like terms and add 18 to both sides;
5x=12+18
5x=30
Divide each side by 5;
=
x=6
Now we know what x= so plug it into equation to find y;
3(6)-2y=12
18-2y=12
-2y=-6
y=3
Don't forget to check your answer;
Hope I didn't lose you, I know there is a lot of steps
=)
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