document.write( "Question 440457: solve by the addition-or-subtraction method: 12a-5b=18 and 15a-5b=30 \n" ); document.write( "

Algebra.Com's Answer #304381 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!

 
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document.write( "Hi
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document.write( "solving by the addition-or-subtraction method: 
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document.write( " 12a-5b=18 and 
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document.write( " 15a-5b=30\r
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document.write( "  12a-5b=  18  
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document.write( " -15a+5b= -30  |mulitply 2nd EQ by -1 to eliminate b
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document.write( "  -3a = -12
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document.write( "    a = 4  and b = 6     (b = (15*4-30)/5 = 6\r
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document.write( "CHECKING our Answer***
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document.write( "   12a-5b=18
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document.write( "    48-30 = 18 \n" );
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