document.write( "Question 389186: Please show me how to Solve the equation x2 + 8x – 2 = 0 using both The quadratic formula and Completing the square.
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Algebra.Com's Answer #275722 by haileytucki(390)\"\" \"About 
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Quadratic First (~=square root)\r
\n" ); document.write( "\n" ); document.write( "x^(2)+8x-2=0\r
\n" ); document.write( "\n" ); document.write( "Use the quadratic formula to find the solutions. In this case, the values are a=1, b=8, and c=-2.
\n" ); document.write( "x=(-b\~(b^(2)-4ac))/(2a) where ax^(2)+bx+c=0\r
\n" ); document.write( "\n" ); document.write( "Use the standard form of the equation to find a, b, and c for this quadratic.
\n" ); document.write( "a=1, b=8, and c=-2\r
\n" ); document.write( "\n" ); document.write( "Substitute in the values of a=1, b=8, and c=-2.
\n" ); document.write( "x=(-8\~((8)^(2)-4(1)(-2)))/(2(1))\r
\n" ); document.write( "\n" ); document.write( "Simplify the section inside the radical.
\n" ); document.write( "x=(-8\6~(2))/(2(1))\r
\n" ); document.write( "\n" ); document.write( "Simplify the denominator of the quadratic formula.
\n" ); document.write( "x=(-8\6~(2))/(2)\r
\n" ); document.write( "\n" ); document.write( "First, solve the + portion of +-.
\n" ); document.write( "x=(-8+6~(2))/(2)\r
\n" ); document.write( "\n" ); document.write( "Factor out the GCF of 2 from each term in the polynomial.
\n" ); document.write( "x=(2(-4)+2(3~(2)))/(2)\r
\n" ); document.write( "\n" ); document.write( "Factor out the GCF of 2 from -8+6~(2).
\n" ); document.write( "x=(2(-4+3~(2)))/(2)\r
\n" ); document.write( "\n" ); document.write( "Reduce the expression (2(-4+3~(2)))/(2) by removing a factor of 2 from the numerator and denominator.
\n" ); document.write( "x=(-4+3~(2))\r
\n" ); document.write( "\n" ); document.write( "Remove the parentheses around the expression -4+3~(2).
\n" ); document.write( "x=-4+3~(2)\r
\n" ); document.write( "\n" ); document.write( "Next, solve the - portion of +-.
\n" ); document.write( "x=(-8-6~(2))/(2)\r
\n" ); document.write( "\n" ); document.write( "Factor out the GCF of 2 from each term in the polynomial.
\n" ); document.write( "x=(2(-4)+2(-3~(2)))/(2)\r
\n" ); document.write( "\n" ); document.write( "Factor out the GCF of 2 from -8-6~(2).
\n" ); document.write( "x=(2(-4-3~(2)))/(2)\r
\n" ); document.write( "\n" ); document.write( "Reduce the expression (2(-4-3~(2)))/(2) by removing a factor of 2 from the numerator and denominator.
\n" ); document.write( "x=(-4-3~(2))\r
\n" ); document.write( "\n" ); document.write( "Remove the parentheses around the expression -4-3~(2).
\n" ); document.write( "x=-4-3~(2)\r
\n" ); document.write( "\n" ); document.write( "The final answer is the combination of both solutions.
\n" ); document.write( "x=-4+3~(2),-4-3~(2)_x=0.2426407,-8.24264\r
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\n" ); document.write( "\n" ); document.write( "Now, completing the square\r
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\n" ); document.write( "\n" ); document.write( "x^(2)+8x-2=0\r
\n" ); document.write( "\n" ); document.write( "Since -2 does not contain the variable to solve for, move it to the right-hand side of the equation by adding 2 to both sides.
\n" ); document.write( "x^(2)+8x=2\r
\n" ); document.write( "\n" ); document.write( "To create a trinomial square on the left-hand side of the equation, add a value to both sides of the equation that is equal to the square of half the coefficient of x. In this problem, add (4)^(2) to both sides of the equation.
\n" ); document.write( "x^(2)+8x+16=2+16\r
\n" ); document.write( "\n" ); document.write( "Add 16 to 2 to get 18.
\n" ); document.write( "x^(2)+8x+16=18\r
\n" ); document.write( "\n" ); document.write( "Factor the perfect trinomial square into (x+4)^(2).
\n" ); document.write( "(x+4)^(2)=18\r
\n" ); document.write( "\n" ); document.write( "Take the square root of each side of the equation to setup the solution for x.
\n" ); document.write( "~((x+4)^(2))=\~(18)\r
\n" ); document.write( "\n" ); document.write( "Remove the perfect root factor (x+4) under the radical to solve for x.
\n" ); document.write( "(x+4)=\~(18)\r
\n" ); document.write( "\n" ); document.write( "Pull all perfect square roots out from under the radical. In this case, remove the 3 because it is a perfect square.
\n" ); document.write( "(x+4)=\3~(2)\r
\n" ); document.write( "\n" ); document.write( "First, substitute in the + portion of the \ to find the first solution.
\n" ); document.write( "(x+4)=3~(2)\r
\n" ); document.write( "\n" ); document.write( "Remove the parentheses around the expression x+4.
\n" ); document.write( "x+4=3~(2)\r
\n" ); document.write( "\n" ); document.write( "Since 4 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 4 from both sides.
\n" ); document.write( "x=-4+3~(2)\r
\n" ); document.write( "\n" ); document.write( "Move all terms not containing x to the right-hand side of the equation.
\n" ); document.write( "x=3~(2)-4\r
\n" ); document.write( "\n" ); document.write( "Next, substitute in the - portion of the \ to find the second solution.
\n" ); document.write( "(x+4)=-3~(2)\r
\n" ); document.write( "\n" ); document.write( "Remove the parentheses around the expression x+4.
\n" ); document.write( "x+4=-3~(2)\r
\n" ); document.write( "\n" ); document.write( "Since 4 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 4 from both sides.
\n" ); document.write( "x=-4+-3~(2)\r
\n" ); document.write( "\n" ); document.write( "Move all terms not containing x to the right-hand side of the equation.
\n" ); document.write( "x=-3~(2)-4\r
\n" ); document.write( "\n" ); document.write( "The complete solution is the result of both the + and - portions of the solution.
\n" ); document.write( "x=3~(2)-4,-3~(2)-4
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