Question 197720
2x-5y=4
5x-7y=-1
solve by using the matrix row reduction method.
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2...-5...4
5...-7...-1
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Multiply thus the 1st row by 5 and the 2nd row by 2 to get:
10...-25...20
10...-14...-2
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Subtract the 1st row from the 2nd to get:
10...-25...20
0.....11...-22
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Divide thru the 2nd row by 11 to get:
10...-25...20
0......1...-2
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Add 25 times the 2nd row to the 1st row to get:
10.....0...-30
0......1...-2
-------------------------
Divide thru the 1st row by 10 to get:
1.....0....-3
0.....1....-2
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Solution: 
x = -3
y = -2
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Cheers,
Stan H.