document.write( "Question 175331: I am trying to find the minimum for f(x)=5x^2-20x+3. i think to find the min. you do -b/2a. In which case i did (-)-20/2(5) and got 2. My teacher said that this answer was incorrect. If you could please tell me where i went wrong it would be much appreciated. thanks! \n" ); document.write( "
Algebra.Com's Answer #130408 by KnightOwlTutor(293)\"\" \"About 
You can put this solution on YOUR website!
You are trying to get the vertex. In order to do this you need to complete the square f(x)=5x^2-20x+3.Set f(x)=0\r
\n" ); document.write( "\n" ); document.write( "0=5x^2-20x+3
\n" ); document.write( "Subtract 3 from both sides\r
\n" ); document.write( "\n" ); document.write( "-3=5x^2-20x
\n" ); document.write( "Factor out the 5 on the right hand side of the equation\r
\n" ); document.write( "\n" ); document.write( "-3=5(x^2-4x\r
\n" ); document.write( "\n" ); document.write( "divide the 4 by 2 and then square it.\r
\n" ); document.write( "\n" ); document.write( "-3=5(x^2-4x+4)\r
\n" ); document.write( "\n" ); document.write( "since you added an additonal 20 on the right side -don't forget to multiply the 4 you just added by 5\r
\n" ); document.write( "\n" ); document.write( "-3+20=5(x-2)^2\r
\n" ); document.write( "\n" ); document.write( "17/5=(x-2)^2\r
\n" ); document.write( "\n" ); document.write( "take the square root of each side 17/5sq rt=x-2\r
\n" ); document.write( "\n" ); document.write( "sqrt85/5=x-2\r
\n" ); document.write( "\n" ); document.write( "add two to both sides\r
\n" ); document.write( "\n" ); document.write( "x=2sqrt85/5\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );