document.write( "Question 235891: For a quadratic function, how do you find the x-intercept(s) \n" ); document.write( "
Algebra.Com's Answer #173656 by nyc_function(2741)\"\" \"About 
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To find the y-intercept, set x = 0 and solve for y.\r
\n" ); document.write( "\n" ); document.write( "To find the x-intercept, set y = 0 and solve for x.\r
\n" ); document.write( "\n" ); document.write( "Sample:\r
\n" ); document.write( "\n" ); document.write( "Given the function f(x) = -2x^2 - 5x + 4, find the intercepts.\r
\n" ); document.write( "\n" ); document.write( "Let x = 0 and solve for y.\r
\n" ); document.write( "\n" ); document.write( "f(0) = -2(0)^2 - 5(0) + 4\r
\n" ); document.write( "\n" ); document.write( "f(0) = 0 + 0 + 4\r
\n" ); document.write( "\n" ); document.write( "f(0) = 4\r
\n" ); document.write( "\n" ); document.write( "The y-intercept is the point (0,4).\r
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\n" ); document.write( "\n" ); document.write( "Now, let y = 0 and solve for x.\r
\n" ); document.write( "\n" ); document.write( "Keep in mind that y = f(x). So, set f(x) = 0 and solve for x.\r
\n" ); document.write( "\n" ); document.write( "0 = -2x^2 - 5x + 4\r
\n" ); document.write( "\n" ); document.write( "2x^2 + 5x - 4 = 0\r
\n" ); document.write( "\n" ); document.write( "This quadratic only factors using the quadratic formula.\r
\n" ); document.write( "\n" ); document.write( "After doing the math, I got:\r
\n" ); document.write( "\n" ); document.write( "x = (-5 ± √57)/4\r
\n" ); document.write( "\n" ); document.write( "So, the x-intercepts are the points ((-5 +√57)/4), 0) and ((-5 -√57)/4), 0).\r
\n" ); document.write( "\n" ); document.write( "The reason I got this odd-looking x value is because the function I selected did not factor other than using the quadratic formula.\r
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