SOLUTION: What are the dimensions of a rectangle that has a perimeter of 30 and its length is 3 times its width?

Question 829233: What are the dimensions of a rectangle that has a perimeter of 30 and its length is 3 times its width?
Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
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2x + 2y = 30
x = 3y
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put the system of linear equations into standard form:
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2x + 2y = 30
x - 3y = 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 = length = 11.25
y = width = 3.75
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system matrix
2 2
1 -3
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inverse of system matrix
0.375 0.25
0.125 -0.25
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determinant of system matrix = -8
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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
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