document.write( "Question 10819: Please help me solve this equation:
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document.write( "19 -(2x +3) = 2(x + 3) +x\r
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document.write( "My attempt:
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document.write( "19 - (2x + 3) = 2(x + 3) +x
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document.write( "19 - 2x + 3 = 2x + 3 +x
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document.write( "19 - 2x + 3 = 3x + 3
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document.write( "19 - 2x + 3 - 3x = + 3
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document.write( "19 +3 -3 = +3 -3
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document.write( "19 = x \n" );
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Algebra.Com's Answer #5690 by longjonsilver(2297)![]() ![]() You can put this solution on YOUR website! Sorry, but your attempt is riddled with wrong algebra.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "First thing is to understand what the question actually says, because from your working, you do not understand. I think you wildly do stuff and hope for the best.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "19 - (2x +3) = 2(x + 3) +x is a shortened version (yes, a lazy version even) for \n" ); document.write( "19 -1*(2x +3) = 2*(x + 3) + 1*x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Mathematicians tend not to write a \"1\" or a \"*\" when we do not need too. But you have to remember they are there.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Secondly, you have to know what to do when you have brackets... the second bracker for example says \"we have (x+3) and we multiply these terms by 2. So we will get a \"2x\" and a \"6\" when we expand the bracket.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Similarly, with the first bracket, we have the (2x+3) and we have to multiply both terms by the -1... giving us -2x and -3. ALWAYS BE CAREFUL with brackets and negatives outside!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So, we get: \n" ); document.write( "19 - (2x +3) = 2(x + 3) + x \n" ); document.write( "19 - 2x - 3 = 2x + 6 + x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now collect like terms together: \n" ); document.write( "19 - 2x - 3 = 2x + 6 + x \n" ); document.write( "16 - 2x = 3x + 6\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now move terms so that all variables (here, the x-terms) are on one side and the numbers are on the other side: \n" ); document.write( "16 - 2x = 3x + 6 --> Add 2x to both sides. \n" ); document.write( "16 = 5x + 6\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "or, 5x + 6 = 16 \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--> now we subtract 6 from both sides to give \n" ); document.write( "5x = 10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--> now, we have 5x, like 5 apples. So, if 5 apples cost 10pence, one apple must cost 2p, yes? How did I do that? I divided both sides by 5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Why did i divide both sides by 5? because i had 5*x and i want to know 1*x. So i have to mess with the 5 without messing the x, so 5/5 is 1. And the one rule of algebra that i have used abouve too, is that \"whatever you do to one side, you HAVE to do to the other side\", so we have 10 and must divide that by 5 too.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so, 5x = 10 \n" ); document.write( "then x = 10/5 \n" ); document.write( "--> x= 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "jon. \n" ); document.write( " \n" ); document.write( " |