document.write( "Question 1089671: This problem was labled in my textbook as a nonlinear equation, but I couldn't find a better spot to put it. \r
\n" );
document.write( "\n" );
document.write( " X^2+y^2=3
\n" );
document.write( "{
\n" );
document.write( " x-y=2\r
\n" );
document.write( "\n" );
document.write( "I'm ending up with x= plus or minus sqrt14/2 my textbook has x as plus or minus 1.
\n" );
document.write( "Could you explain to me where I'm going wrong?\r
\n" );
document.write( "\n" );
document.write( "Thank you!\r
\n" );
document.write( "\n" );
document.write( "p.s. I wasn't quite sure how to notate the fact that the two equations went together so I just did the little brackets between them. I'm not a math person, so if you could be very clear and explicit that would be much appreciated. Thanks again! \n" );
document.write( "
Algebra.Com's Answer #704012 by Theo(13342)![]() ![]() You can put this solution on YOUR website! your equations are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x^2 + y^2 = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x - y = 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "right off the bat, the book can't be right when it says x is plus or minus 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "assuming x is 1, then x^2 + y^2 = 3 becomes 1 + y^2 = 3 which becomes y^2 = 2 which becomes y = plus or minus sqrt(2).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "assuming x is -1, you get the same value for y as y = sqrt(2) becauswe (-1)^2 is also equal to 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "however:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x - y = 2 becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1 - sqrt(2) = 2 which is false, so x = plus or minus 1 can't be the solution because it doesn't solve both equations simultaneosuly, which i assume is what the problem wants you to solve.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solution of x = sqrt(14)/2 doesn't look right either.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i solved it as follows:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "start with:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x^2 + y^2 = 3 \n" ); document.write( "x - y = 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "these are 2 equations that need to be solved simultaneously.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for y in the second equation to get y = x - 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "replace y with x-2 in the first equation to get x^2 + (x-2)^2 = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get x^2 + x^2 - 4x + 4 = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get 2x^2 - 4x + 4 = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract 3 from both sides of the equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x^2 - 4x + 1 = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "factor this quadratic to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 1.7071067811865 or x = 0.29289321881345\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i used an online quaderatic solver at https://www.mathsisfun.com/quadratic-equation-solver.html\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i also solved it manually using the quadratic formula and got:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 1 + sqrt(2)/2 or x = 1 - sqrt(2)/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this resulted in:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 1.707106781 or x = .2928932188\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the results are the same with the exception of the number of decimal digits displayed.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |