document.write( "Question 1120176: Given the quadratic function f(x) = 2x2– 8x + 11
\n" ); document.write( "Use “completing the squares” to convert the quadratic function into vertex form
\n" ); document.write( "State the vertex, Find the x- and y-intercepts, Graph the function\r
\n" ); document.write( "\n" ); document.write( "the end answer is 2(x-2)^2 +3, I need the steps in-between the problem and the answer
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Algebra.Com's Answer #735841 by greenestamps(13198)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "You might want to look at the lesson tutor @ikleyn suggested in her response. Completing the square is a skill you might need in a lot of different types of math problems.

\n" ); document.write( "In case they might help your understanding of the process, let me add a few notes of explanation to the solution as she showed it....

\n" ); document.write( "\"2x%5E2-8x%2B11\"

\n" ); document.write( "Ignore the constant term for the moment; you need to complete the square in the variable x.
\n" ); document.write( "\"%282x%5E2-8x%29%2B11\"

\n" ); document.write( "To complete the square, you need to factor out the leading coefficient:
\n" ); document.write( "\"2%28x%5E2-4x%29%2B11\"

\n" ); document.write( "Think of the pattern for squaring a binomial: (x+a)^2 = x^2+2ax+a^2. The coefficient of the middle term in the product is twice the constant term in the binomial. So to complete a square you need to take half the coefficient of the linear term and square it.

\n" ); document.write( "In this example, the coefficient of the linear term is -4; half of that squared is (-2)^2 = 4. You need to complete the square in the parentheses by adding 4.

\n" ); document.write( "Note that you have added 4 inside the parentheses, so you have added 2*4=8 to the expression as a whole. To balance that, you need to subtract 8 from the expression (outside of the parentheses).
\n" ); document.write( "\"2%28x%5E2-4x%2B4%29%2B11-8\"

\n" ); document.write( "Now write the trinomial as a binomial squared, and simplify the rest of the expression.
\n" ); document.write( "\"2%28x-2%29%5E2%2B3\"

\n" ); document.write( "The square of a number is always 0 or positive, so the minimum value of the expression will be when (x-2) is zero -- i.e., when x=2. And the value of the expression when x=2 is 2(0^2)+3 = 3. So the vertex of the graph is (2,3).
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