<PRE><B>Question 829699</B>
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x = 3y
x + y = 720
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put the system of linear equations into standard form:
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x - 3y = 0
x + y = 720
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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 = 540
y = 180
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system matrix
1 -3
1 1
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inverse of system matrix
0.25 0.75
-0.25 0.25
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determinant of system matrix = 4
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Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
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Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
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Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php</PRE>