document.write( "Question 808851: We glued together several unit cubes to make a solid (no hole in the
\n" ); document.write( "middle) big cube. There are a total of 80 unit cubes that are either at the
\n" ); document.write( "vertices or on the edges of the big cube. How many unit cubes did we use
\n" ); document.write( "to build the big cube? \n" ); document.write( "

Algebra.Com's Answer #487236 by josmiceli(19441) $\"\"$ $\"About$

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If I say that $\"+x+\"$ is the number of cubes
\n" ); document.write( "along an edge including the corners, then
\n" ); document.write( " $\"+x+-+2+\"$ is the number not including
\n" ); document.write( "the corners.
\n" ); document.write( "Going around the cube I have $\"+12+\"$
\n" ); document.write( "edges and $\"+8+\"$ corners, so
\n" ); document.write( " $\"+12%2A%28+x+-+2+%29+%2B+8+=+80+\"$
\n" ); document.write( " $\"+12x+-+24+%2B+8+=+80+\"$
\n" ); document.write( " $\"+12x+=+80+%2B+16+\"$
\n" ); document.write( " $\"+12x+=+96+\"$
\n" ); document.write( " $\"+x+=+8+\"$
\n" ); document.write( "-------------
\n" ); document.write( "The number of unit cubes should be
\n" ); document.write( " $\"+8%5E3+=+512+\"$
\n" ); document.write( "512 unit cubes\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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