document.write( "Question 825550: meg sold 3 packs of gum and 3 sticks of gum for $48. joe sold 7 packs and 9 sticks for $132. what is the cost of one pack and one stick of gum? \n" ); document.write( "

Algebra.Com's Answer #497435 by TimothyLamb(4379) $\"\"$ $\"About$

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---
\n" ); document.write( "x = price per pack
\n" ); document.write( "y = price per stick
\n" ); document.write( "---
\n" ); document.write( "3x + 3y = 48
\n" ); document.write( "7x + 9y = 132
\n" ); document.write( "---
\n" ); document.write( "copy and paste the above linear system in standard form into this matrix-method solver:
\n" ); document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php
\n" ); document.write( "---
\n" ); document.write( "solution by matrix method:
\n" ); document.write( "x = 6
\n" ); document.write( "y = 10
\n" ); document.write( "---
\n" ); document.write( "system matrix
\n" ); document.write( "3 3
\n" ); document.write( "7 9
\n" ); document.write( "---
\n" ); document.write( "inverse of system matrix
\n" ); document.write( "1.5 -0.5
\n" ); document.write( "-1.1666667 0.5
\n" ); document.write( "---
\n" ); document.write( "determinant of system matrix = 6
\n" ); document.write( "---
\n" ); document.write( "now solve by elimination method:
\n" ); document.write( "---
\n" ); document.write( "(3x + 3y = 48)7
\n" ); document.write( "(7x + 9y = 132)-3
\n" ); document.write( "---
\n" ); document.write( "21x + 21y = 336
\n" ); document.write( "-21x - 27y = -396
\n" ); document.write( "---
\n" ); document.write( "add the system:
\n" ); document.write( "-6y = -60
\n" ); document.write( "---
\n" ); document.write( "y = 10
\n" ); document.write( "---
\n" ); document.write( "3x + 3y = 48
\n" ); document.write( "3x + 3(10) = 48
\n" ); document.write( "3x = 18
\n" ); document.write( "---
\n" ); document.write( "x = 6
\n" ); document.write( "---
\n" ); document.write( "solution by elimination method:
\n" ); document.write( "x = 6
\n" ); document.write( "y = 10
\n" ); document.write( "---
\n" ); document.write( "NOTE:
\n" ); document.write( "solution by matrix method agrees with solution by elimination method
\n" ); document.write( "---
\n" ); document.write( "Solve and graph linear equations:
\n" ); document.write( "https://sooeet.com/math/linear-equation-solver.php
\n" ); document.write( "---
\n" ); document.write( "Solve quadratic equations, quadratic formula:
\n" ); document.write( "https://sooeet.com/math/quadratic-formula-solver.php
\n" ); document.write( "---
\n" ); document.write( "Solve systems of linear equations up to 4-equations 4-variables:
\n" ); document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php \n" ); document.write( "

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