document.write( "Question 104710: x-2*sqrt(x-3)=3\r
\n" ); document.write( "\n" ); document.write( "solve for zero...\r
\n" ); document.write( "\n" ); document.write( "I subtract x from both sides which =\r
\n" ); document.write( "\n" ); document.write( "-2*sqrt(x-3)=3-x\r
\n" ); document.write( "\n" ); document.write( "then I divide by -2 from both sides\r
\n" ); document.write( "\n" ); document.write( "sqrt(x-3)=(3-x)/-2\r
\n" ); document.write( "\n" ); document.write( "then to get rid of the \"sqrt\" ^2 on both sides\r
\n" ); document.write( "\n" ); document.write( "x-3=(9+x^2)/4\r
\n" ); document.write( "\n" ); document.write( "then I subtract \"x\" and add 3 to both sides to solve for zero.\r
\n" ); document.write( "\n" ); document.write( "0=(9+x^2)/4-x+3\r
\n" ); document.write( "\n" ); document.write( "then I find a common denominator of 4 and solve\r
\n" ); document.write( "\n" ); document.write( "0=(9+x^2)/4 -4x/4+12/4 which equals 0=(x^2-4x+21)/4\r
\n" ); document.write( "\n" ); document.write( "then I multiply 4/1 on both side the loose the denominator.\r
\n" ); document.write( "\n" ); document.write( "0=x^2-4x+21 which can not be factored, but my text book gives a solution set of {7,3}. I cant find were I went wrong, please help.
\n" ); document.write( "Please note, this question had already been answered but the link to the answer did not work so this is why I am re-submitting it. Thank you.
\n" ); document.write( "

Algebra.Com's Answer #76202 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"x-2%2Asqrt%28x-3%29=3\" Start with the given equation\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-2%2Asqrt%28x-3%29=3-x\" Subtract x from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"sqrt%28x-3%29=%283-x%29%2F-2\" Divide both sides by -2\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x-3=%28%283-x%29%2F-2%29%5E2\" Square both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now this is where you went wrong, when you square \"3-x\" you need to foil it to get \"9-6x%2Bx%5E2\" instead of \"9%2Bx%5E2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x-3=%289-6x%2Bx%5E2%29%2F4\" Foil the numerator and square the denominator\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%289-6x%2Bx%5E2%29%2F4%2B3\" Add 3 to both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%289-6x%2Bx%5E2%29%2F4%2B3%284%2F4%29\" Multiply 3 by \"4%2F4\" \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%289-6x%2Bx%5E2%29%2F4%2B12%2F4\" Multiply \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%289-6x%2Bx%5E2%2B12%29%2F4\" Add the fractions\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%28-6x%2Bx%5E2%2B21%29%2F4\" Combine like terms\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"4x=-6x%2Bx%5E2%2B21\" Multiply both sides by 4\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"0=-6x%2Bx%5E2%2B21-4x\" Subtract 4x from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"0=x%5E2%2B21-10x\" Combine like terms\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"0=x%5E2-10x%2B21\" Rearrange the terms\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( "
Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:

\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " Starting with the general quadratic
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"ax%5E2%2Bbx%2Bc=0\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " the general solution using the quadratic equation is:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So lets solve \"x%5E2-10%2Ax%2B21=0\" ( notice \"a=1\", \"b=-10\", and \"c=21\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%28--10+%2B-+sqrt%28+%28-10%29%5E2-4%2A1%2A21+%29%29%2F%282%2A1%29\" Plug in a=1, b=-10, and c=21
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+sqrt%28+%28-10%29%5E2-4%2A1%2A21+%29%29%2F%282%2A1%29\" Negate -10 to get 10
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+sqrt%28+100-4%2A1%2A21+%29%29%2F%282%2A1%29\" Square -10 to get 100 (note: remember when you square -10, you must square the negative as well. This is because \"%28-10%29%5E2=-10%2A-10=100\".)
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+sqrt%28+100%2B-84+%29%29%2F%282%2A1%29\" Multiply \"-4%2A21%2A1\" to get \"-84\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+sqrt%28+16+%29%29%2F%282%2A1%29\" Combine like terms in the radicand (everything under the square root)
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+4%29%2F%282%2A1%29\" Simplify the square root (note: If you need help with simplifying the square root, check out this solver)
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B-+4%29%2F2\" Multiply 2 and 1 to get 2
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So now the expression breaks down into two parts
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x+=+%2810+%2B+4%29%2F2\" or \"x+=+%2810+-+4%29%2F2\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Lets look at the first part:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x=%2810+%2B+4%29%2F2\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x=14%2F2\" Add the terms in the numerator
\n" ); document.write( "
\n" ); document.write( " \"x=7\" Divide
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So one answer is
\n" ); document.write( "
\n" ); document.write( " \"x=7\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Now lets look at the second part:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x=%2810+-+4%29%2F2\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x=6%2F2\" Subtract the terms in the numerator
\n" ); document.write( "
\n" ); document.write( " \"x=3\" Divide
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So another answer is
\n" ); document.write( "
\n" ); document.write( " \"x=3\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So our solutions are:
\n" ); document.write( "
\n" ); document.write( " \"x=7\" or \"x=3\"
\n" ); document.write( "
\n" ); document.write( "

\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So this means the solution set is {7,3}
\n" ); document.write( "
\n" );