document.write( "Question 211912: How do you figure out this problem: -5x(2x-1)=3(x+4) \n" ); document.write( "
Algebra.Com's Answer #160094 by drj(1380)\"\" \"About 
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How do you figure out this problem: -5x(2x-1)=3(x+4) \r
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\n" ); document.write( "\n" ); document.write( "Step 1. Multiply everything out on both sides of the equation. After we mess around with the equation, we will get a quadratic equation. Here it goes:\r
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\n" ); document.write( "\n" ); document.write( " -5x(2x-1)=3(x+4) will yield: -10x^2+5x=3x+12.\r
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\n" ); document.write( "\n" ); document.write( "Step 2. Now let's put everything on the right side so that the left side is zero. I like a positive number for the x^2 term. \r
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\n" ); document.write( "\n" ); document.write( " Step 2a. Add 10x^2 to both sides of equation in Step 1: \r
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\n" ); document.write( "\n" ); document.write( " 10x^2-10x^2+5x=10x^2+3x+12\r
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\n" ); document.write( "\n" ); document.write( "Note: The 10x^2 terms cancel out on the left side.\r
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\n" ); document.write( "\n" ); document.write( " Step 2b. Simplify equation in step 2a. \r
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\n" ); document.write( "\n" ); document.write( " 5x=10x^2+3x+12\r
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\n" ); document.write( "\n" ); document.write( "Step 3. Subtract 5x both sides of equation in Step 2b to make left side =0.\r
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\n" ); document.write( "\n" ); document.write( " 5x-5x=10x^2+3x-12-5x\r
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\n" ); document.write( "\n" ); document.write( "Note: Collect like terms and simplify 3x-5x=-2x\r
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\n" ); document.write( "\n" ); document.write( " Step 3a. Simplify to yield our final equation \r
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\n" ); document.write( "\n" ); document.write( " 0=10x^2-2x-12 OR 10x^2-2x-12=0\r
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\n" ); document.write( "\n" ); document.write( "Step 4. Now we have a quadratic equation in step 3a.\r
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\n" ); document.write( "\n" ); document.write( " \"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"\r
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\n" ); document.write( "\n" ); document.write( "where a=10, b=-2, and c=-12.\r
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\n" ); document.write( "\n" ); document.write( "Step 5. Substitute a, b, and c in the formula. The steps are shown below:\r
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\n" ); document.write( "\n" ); document.write( "Note when the quadratic equation is a parabola when the values of x are real numbers. See graph where it intersects the x-axis. This is when y=0, hence our quadratic equation.\r
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"10x%5E2%2B-2x%2B-12+=+0\") has the following solutons:
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\n" ); document.write( " \"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%28-2%29%5E2-4%2A10%2A-12=484\".
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\n" ); document.write( " Discriminant d=484 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--2%2B-sqrt%28+484+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%28-2%29%2Bsqrt%28+484+%29%29%2F2%5C10+=+1.2\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-2%29-sqrt%28+484+%29%29%2F2%5C10+=+-1\"
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\n" ); document.write( " Quadratic expression \"10x%5E2%2B-2x%2B-12\" can be factored:
\n" ); document.write( " \"10x%5E2%2B-2x%2B-12+=+10%28x-1.2%29%2A%28x--1%29\"
\n" ); document.write( " Again, the answer is: 1.2, -1.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+10%2Ax%5E2%2B-2%2Ax%2B-12+%29\"

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\n" ); document.write( "\n" ); document.write( "For Step-By-Step Videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra \r
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