Question 705877
SOLVE STEP BY STEP THANK YOU:)
1) x+y=5
   3x-y=7
---------- Add
That method is elimination.
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2) 2x+y=3
  -2x+5y=-9
Same as #1
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3) 3x+5y=0
   2x-5y=-25
Same as #1
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4) -4x-y=-6
   4x+3y=18
5) 2x-y=-5
   -2x-5y=11
6) 8=4x-3y
   17=x+3y
7) -6=3x+y
   10=-5x-y
8) 3x+8y=-1
   -3x+y=-17
4 thru 8 same as #1
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9) x+2y=15
   5x=2y+3 --> 5x-2y = 3
Then same as #1
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10) 7x-y=12
    -3y=7x+8
Rearrange, then ...
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11) y=3x+13
    2x=y-9
You can do it like #1, elimination, or you can use substitution.
Since y is given in the 1st eqn, sub for it in the 2nd.
2x = y - 9
2x = 3x+13 - 9
Then solve for x, etc
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12) 4x+12=-7y
    -y+12=4x
Rearrange, then subtract.
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13) 3x+2y=6
    y=x+3
Sub for y in the 1st eqn
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14) -x+4y=-4
    y=x-1
Same as #13
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15) -300x-125y=1350
    y+2=8
No x in the 2nd eqn --> y = 6
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16) 2x-y=6
    1/6x-1/12y=1/2
Multiply eqn 2 by 12 to eliminate fractions.
Then the 2 equations are the same.
--> dependent, and infinite # of solutions.
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17)4x+4y=5
   x-4y=-5/2
--------------- Add
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18) -2x+y=-6
    6x-13y=-12
Multiply the 1st eqn by 3, then add
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19) 2(x+2y)=12 --> x + 2y = 6
    -6x=5y-8
Solve eqn 1 for x, sub for x in eqn 2
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Pick the best method for the rest.
20) 5x-2y=-25
    10x=3(y-10)
21) 5(3x-y)=10
    4y=7x-3
22) 2x=-3(y+3)
    3x-4y=-22
23) 2x-5=7
    4=3y+1
24) -2=4-2y
    7x-5=-5