SOLUTION: Solve using the substitution method, the elimination method, or the graphing method. 5. 2(x-y) = 3x + x, x = 3y + 4 6. y = two-fifths – 7, y = two-fifths + 4 I

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve using the substitution method, the elimination method, or the graphing method. 5. 2(x-y) = 3x + x, x = 3y + 4 6. y = two-fifths – 7, y = two-fifths + 4 I       Log On


   

Question 273616: Solve using the substitution method, the elimination method, or the graphing method.
5. 2(x-y) = 3x + x,
x = 3y + 4
6. y = two-fifths – 7,
y = two-fifths + 4
I need help in solving these
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
5. 2(x-y) = 3x + x
2x-2y=4x
2x-4x-2y=0
-2x-2y=0
x=3y+4
x-3y=4 multiply by 2 & add.
2x-3y=4
-2x-2y=0
--------------
-5y=0
y=0 ans.
x=3*0+4
x=4 ans.
Proof:
2(4-0)=3*2+2
8=6+2
8=8
-----------------------
6. y = two-fifths – 7
y = two-fifths + 4
y=2/5-7 or y=.4-7 or y=-6.6
y=2/5+4 or y=.4+4 or y=4.4
Graphically these lines are parallel thus there is no unique solution for x & y.
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+y+=+-6.6%2C+y+=+4.4%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = -6.6 and y = 4.4).