SOLUTION: The sum of the digits of a two-digit number is 7. With the digits reversed the number is 5 times the tens digit of the original number. Find the original number.

Question 825433: The sum of the digits of a two-digit number is 7. With the digits reversed the number is 5 times the tens digit of the original number. Find the original number.
Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
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x = ones digit
y = tens digit
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x + y = 7
10x + y = 5y
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put the system of linear equations into standard form
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x + y = 7
10x - 4y = 0
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copy and paste the above linear system in standard form into this matrix-method solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = 2
y = 5
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system matrix
1 1
10 -4
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inverse of system matrix
0.28571429 0.071428571
0.71428571 -0.071428571
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determinant of system matrix = -14
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answer:
the original number is: 52
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Solve systems of linear equations up to 4-equations 4-variables:
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