Question 89812: 3x+4y=2
x-y=1
Answer by tutorcecilia(2152)   (Show Source):
You can put this solution on YOUR website! This system of equations can be solved using several different methods:
Elimination (addition or subtraction)
Substitution (solving for one variable)
Graphing ( Graphing both equations and finding their common cooridate point)
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I wil use the method of substitution:
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3x+4y=2
x-y=1 [solve for the x (or the y) term]
x=y+1 [substitute (y+1) for (x) in the other equation and solve for the y-term]
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3x+4y=2
3(y+1)+4y=2 [simplify]
3y+3 + 4y = 2
7y + 3 =2
7y +3 - 3 = 3 - 3
7y = -1
7y/7=-1/7
y=-1/7 [plug (y=-1/7 ) back into either original equation and solve for the x-term]
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3x+4y=2
3x+4(-1/7)=2
3x -4/7 = 2
3x-4/7 + 4/7=2+4/7
3x=14/7 + 4/7
3x=18/7
3x/3=18/(7*3)
x=18/21
x=6/7 [plug (x=6/7) and plug (y = -1/7) back into either original equation and solve the equation]
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x-y=1
(6/7)-(-1/7)=1
6/7 + 1/7 = 1
7/7=1
1=1 [checks out]
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