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You can put this solution on YOUR website!
\n" ); document.write( "Tutor @math_helper has given you a good step-by-step demonstration of a formal algebraic way to solve your problem.
\n" ); document.write( "Tutor @josgarithmetic has hinted at a method for solving the problem informally, using logical reasoning.
\n" ); document.write( "And if you do what he SUGGESTS that you do, you find that the formal algebra does EXACTLY the same thing as the informal solution.
\n" ); document.write( "Think about what the given equation says. It says you took a number, multiplied it by 10, then added 2, and ended up with a result of 7.
\n" ); document.write( "The informal method of solving the problem says that to get back where you started, you need to \"undo\" the things you did to the original number.
\n" ); document.write( "The last thing you did to get your final answer of 7 was add 2; to undo that, you need to subtract 2. 7-2 = 5.
\n" ); document.write( "In the formal algebraic solution, that looks like this (as shown in @math_helper's solution):
\n" ); document.write( "10x + 2 = 7 --> 10x + 2 - 2 = 7 - 2 --> 10x = 5
\n" ); document.write( "Continuing to work backwards, the first thing you did to the number you started with was multiply by 10. To undo that, you need to divide by 10. Informally, you simply say 5 divided by 10 is 5/10, or 1/2; so that is the number you started with.
\n" ); document.write( "In the formal algebraic solution, that step looks like this:
\n" ); document.write( "10x = 5 --> 10x/10 = 5/10 --> x = 5/10 = 1/2 \n" ); document.write( "