document.write( "Question 827520: If 100 students took a test, the class average was 76%. The girls averaged 70% and the boys averaged 80% how many girls participated in the test \n" ); document.write( "
Algebra.Com's Answer #498734 by TimothyLamb(4379)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "x = boys
\n" ); document.write( "y = girls
\n" ); document.write( "---
\n" ); document.write( "x + y = 100
\n" ); document.write( "80x + 70y = 76*100
\n" ); document.write( "---
\n" ); document.write( "put the system of linear equations into standard form:
\n" ); document.write( "---
\n" ); document.write( "x + y = 100
\n" ); document.write( "80x + 70y = 7600
\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:
\n" ); document.write( "x = boys = 60
\n" ); document.write( "y = girls = 40
\n" ); document.write( "---
\n" ); document.write( "system matrix
\n" ); document.write( "1 1
\n" ); document.write( "80 70
\n" ); document.write( "---
\n" ); document.write( "inverse of system matrix
\n" ); document.write( "-7 0.1
\n" ); document.write( "8 -0.1
\n" ); document.write( "---
\n" ); document.write( "determinant of system matrix = -10
\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 6-equations 6-variables:
\n" ); document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php \n" ); document.write( "
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