document.write( "Question 1108162: A student draw 12 ,figures of either is a triangle or a rectangle in a paper. the total number of sides of the figures is 44, find the numbers of rectangles \n" ); document.write( "

Algebra.Com's Answer #723145 by ikleyn(52781) $\"\"$ $\"About$

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document.write( " x +  y = 12,    (1)     (x = #of triangles,  y = #of rectangles)\r\n" );
document.write( "3x + 4y = 44.    (2)     (number of sides)\r\n" );
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document.write( "From eq(1),  y = 12-x.  Substitute it into eq(2).  You will get\r\n" );
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document.write( "3x + 4*(12-x) = 44\r\n" );
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document.write( "3x + 48 - 4x = 44,\r\n" );
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document.write( "-x = 44 - 48 = -4  ====>  x = 4.\r\n" );
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document.write( "Answer.  4 triangles and 12-4 = 8 rectangles.\r\n" );
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