document.write( "Question 23329: Can you help me with this problem and help me sketch a graph
\n" ); document.write( "y = x^2 + 2x -24\r
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Algebra.Com's Answer #12107 by philberg99(10)\"\" \"About 
You can put this solution on YOUR website!
First of all, look at the coefficient of the \"x%5E2\" term. If it is positive, then the parabola is shaped up. If it is negative, the parabola is shaped down. The coefficient of the \"x%5E2\" term is 1 so it is shaped up.\r
\n" ); document.write( "\n" ); document.write( "Now we have to figure out where the parabola crosses the x axis. To do this, set the equation equal to zero. \r
\n" ); document.write( "\n" ); document.write( "0 = \"x%5E2+%2B+2%2Ax+-+24\"
\n" ); document.write( "0 = (x - 4)(x + 6)
\n" ); document.write( "0 = x - 4, 0 = x + 6\r
\n" ); document.write( "\n" ); document.write( "So x = 4, x = -6 are our solutions.\r
\n" ); document.write( "\n" ); document.write( "Finally, you may need to find the lowest point of this parabola, called the vertex. To find the x coordinate of the vertex, use the formula x = \"%28-b%29%2F%282%2Aa%29\" where a is the coefficient of the \"x%5E2\" term and b is the coefficient of the \"x\" term. So x = \"%28-2%29%2F%282%2A1%29%7D%7D%2C+so+x+=+%7B%7B%7B%28-2%29%2F2\" = -1. To find the y value that goes with the -1, substitute -1 in for x. That gives us y = (-1)^2 + 2(-1) - 24 = 1 - 2 - 24 = -25. So the vertex, or the lowest point of the parabola is (-1, -25).
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