document.write( "Question 88061: how can i solve this equation for x and check my result ..please help\r
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document.write( "7(3x + 4) =8(2x +5) + 13 \n" );
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Algebra.Com's Answer #64043 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! Given: \n" ); document.write( ". \n" ); document.write( "7(3x + 4) =8(2x +5) + 13 \n" ); document.write( ". \n" ); document.write( "To solve this equation, first do the distributed multiplications on the left and right sides ... \n" ); document.write( "that is multiply the 7 times both the 3x and the +4 and on the right side multiply the 8 by \n" ); document.write( "the 2x and the +5. When you do those two multiplications you get: \n" ); document.write( ". \n" ); document.write( "21x + 28 = 16x + 40 + 13 \n" ); document.write( ". \n" ); document.write( "The next goal will be to get all the terms containing x on the left side of the equation. \n" ); document.write( "You can do this by recognizing that you need to get rid of the 16x on the right side. Do \n" ); document.write( "that by subtracting 16x from the right side. But in an equation, if you subtract 16x from \n" ); document.write( "one side then you must also subtract 16x from the other side. This makes the \n" ); document.write( "equation become: \n" ); document.write( ". \n" ); document.write( "21x - 16x + 28 = 16x - 16x + 40 + 13 \n" ); document.write( ". \n" ); document.write( "On the right side the 16x and the -16x cancel each other so the equation reduces to: \n" ); document.write( ". \n" ); document.write( "21x - 16x + 28 = 40 + 13 \n" ); document.write( ". \n" ); document.write( "The next goal is to get all the numbers on the right side of the equation. You can do that \n" ); document.write( "by getting rid of the 28 on the left side of the equation, and that is done by subtracting 28 \n" ); document.write( "from both sides. Subtracting 28 from both sides results in: \n" ); document.write( ". \n" ); document.write( "21x - 16x + 28 - 28 = 40 + 13 - 28 \n" ); document.write( ". \n" ); document.write( "On the left side the 28 and the -28 cancel each other out and the equation then becomes: \n" ); document.write( ". \n" ); document.write( "21x - 16x = 40 + 13 - 28 \n" ); document.write( ". \n" ); document.write( "Now combine the terms on both sides. On the left side when you subtract 16x from 21x, the \n" ); document.write( "result is 5x. And on the right side, when you add 40 plus 13 and then subtract 28 the \n" ); document.write( "result is 25. This means the equation becomes: \n" ); document.write( ". \n" ); document.write( "5x = 25 \n" ); document.write( ". \n" ); document.write( "Now you can solve for x by dividing both sides by 5 which is the multiplier of x. This \n" ); document.write( "reduces the equation to: \n" ); document.write( ". \n" ); document.write( "x = 5 \n" ); document.write( ". \n" ); document.write( "You now have the answer for x. To check, go back to the original equation and substitute 5 \n" ); document.write( "in the place of x and see if both sides of the equation are equal to each other. \n" ); document.write( ". \n" ); document.write( "The original equation was: \n" ); document.write( ". \n" ); document.write( "7(3x + 4) =8(2x +5) + 13 \n" ); document.write( ". \n" ); document.write( "Replacing x with 5 results in: \n" ); document.write( ". \n" ); document.write( "7(3*5 + 4) = 8(2*5 + 5) + 13 \n" ); document.write( ". \n" ); document.write( "Do the multiplications of the terms inside the parentheses to get: \n" ); document.write( ". \n" ); document.write( "7(15 + 4) = 8(10 + 5) + 13 \n" ); document.write( ". \n" ); document.write( "Add the numbers inside the parentheses: \n" ); document.write( ". \n" ); document.write( "7(19) = 8(15) + 13 \n" ); document.write( ". \n" ); document.write( "Multiply 7 times 19 and 8 times 15 to get: \n" ); document.write( ". \n" ); document.write( "133 = 120 + 13 \n" ); document.write( ". \n" ); document.write( "Add the two numbers on the right side: \n" ); document.write( ". \n" ); document.write( "122 = 133 \n" ); document.write( ". \n" ); document.write( "When x equals 5 both sides of the equation equal 133, so the equation works when x = 5. \n" ); document.write( "Therefore, the answer of x = 5 is correct. \n" ); document.write( ". \n" ); document.write( "Hope this helps you to understand the problem and how to apply some basic rules for solving equations.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |