document.write( "Question 198474: Hi!\r
\n" ); document.write( "\n" ); document.write( "Solve the equation (1+sqrt(x))^2-2(1+sqrt(x))-15=0\r
\n" ); document.write( "\n" ); document.write( "thanks!\r
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Algebra.Com's Answer #148996 by MRperkins(300)\"\" \"About 
You can put this solution on YOUR website!
There is probably more than one way to solve this, but the easiest way is actually quite easy and I am sure you will understand it once we are done.
\n" ); document.write( "First, notice that the first term is \"%281%2Bsqrt%28x%29%29%5E2\" and the second term is \"-2%2A%281%2Bsqrt%28x%29%29\"
\n" ); document.write( "Now, select any variable to replace \"1%2Bsqrt%28x%29\" let's say z
\n" ); document.write( "so now substitute z for \"1%2Bsqrt%28x%29\" and you get a problem that you better understand which is \"z%5E2-2z-15=0\"\r
\n" ); document.write( "\n" ); document.write( "Now you can factor the problem to factors of 15 that subtract and give you -2 which are -5 and 2
\n" ); document.write( "so you get \"%28z-5%29%28z%2B2%29=0\" which means either z-5=0 or z+2=0
\n" ); document.write( "so z=5 or z=-2\r
\n" ); document.write( "\n" ); document.write( "Substitute \"1%2Bsqrt%28x%29\" for z and you get:
\n" ); document.write( "\"1%2Bsqrt%28x%29=5\" and \"1%2Bsqrt%28x%29=-2\"
\n" ); document.write( "\"sqrt%28x%29=4\" and \"sqrt%28x%29=-3\"
\n" ); document.write( "square both sides and you get
\n" ); document.write( "x=16 and x=9\r
\n" ); document.write( "\n" ); document.write( "check your answers by plugging in your answers
\n" ); document.write( "1. \"%281%2Bsqrt%2816%29%29%5E2-2%281%2Bsqrt%2816%29%29-15=0\"
\n" ); document.write( "\"%281%2B4%29%5E2-2%285%29-15=0\"
\n" ); document.write( "\"25-10-15=0\" 0=0 so 16 does work!\r
\n" ); document.write( "\n" ); document.write( "2.\"%281%2Bsqrt%289%29%29%5E2-2%281%2Bsqrt%289%29%29-15=0\"
\n" ); document.write( "\"%281%2B3%29%5E2-2%281%2B3%29-15=0\"
\n" ); document.write( "\"16-8-15=0\" -7 does not equal 0 so 9 does not work. Therefore, your only real answer is x=16\r
\n" ); document.write( "\n" ); document.write( "I hope this helps!
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