document.write( "Question 308442: four times the square root of the quantity of 3a+4 equals a+13. I know the answers are 7 and 15 but cannot figure out how to get them algebraically \n" ); document.write( "

Algebra.Com's Answer #220521 by JBarnum(2146) $\"\"$ $\"About$

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$\"4%28sqrt%283a%2B4%29%29=a%2B13\"$ square everything
\n" ); document.write( " $\"4%5E2%28sqrt%283a%2B4%29%29%5E2=%28a%2B13%29%5E2\"$
\n" ); document.write( " $\"16%283a%2B4%29=%28a%2B13%29%28a%2B13%29\"$ distribute
\n" ); document.write( " $\"48a%2B64=a%5E2%2B26a%2B169\"$ subtract 48a and 64 from both sides
\n" ); document.write( " $\"0=a%5E2-22a%2B105\"$ -7 and -15 both multiply to get +105 and add to get -22
\n" ); document.write( " $\"0=%28a-7%29%28a-15%29\"$
\n" ); document.write( " $\"highlight%287=a%29\"$ $\"highlight%2815=a%29\"$ \n" ); document.write( "

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