document.write( "Question 1131679: 1) Write the quadratic function rule that has a vertex at (-2,5) and is stretched by a factor of 2 and reflected across the x axis.\r
\n" ); document.write( "\n" ); document.write( "2) The vertex of a quadratic function is (1,-50). F(5) = -18. Find the function rule, find the roots, and find the y intercept.\r
\n" ); document.write( "\n" ); document.write( "3) The roots of a quadratic function are -3 and 7. The quadratic coefficient is -1/5. write the rule in factored form and find the maximum of the function
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Algebra.Com's Answer #748650 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "1) vertex at (-2,5); stretched by a factor of 2 and reflected across the x axis

\n" ); document.write( "\"y+=+a%28x%2B2%29%5E2%2B5\"

\n" ); document.write( "with the stretch by a factor of 2 and a reflection across the x-axis, the coefficient a is -2. So

\n" ); document.write( "\"y+=+-2%28x%2B2%29%5E2%2B5\"

\n" ); document.write( "2) vertex (1,-50); f(5) = -18

\n" ); document.write( "\"y+=+a%28x-1%29%5E2-50\"

\n" ); document.write( "find the value of the coefficient a using the (x,y) coordinates of the given point, (5,-18).

\n" ); document.write( "\"-18+=+a%285-1%29%5E2-50\"
\n" ); document.write( "\"-18+=+16a-50\"
\n" ); document.write( "\"32+=+16a\"
\n" ); document.write( "\"a+=+2\"

\n" ); document.write( "\"y+=+2%28x-1%29%5E2-50\"

\n" ); document.write( "roots: set y = 0 and solve.

\n" ); document.write( "\"0+=+2%28x-1%29%5E2-50\"
\n" ); document.write( "\"2%28x-1%29%5E2+=+50\"
\n" ); document.write( "\"%28x-1%29%5E2+=+25\"
\n" ); document.write( "\"x-1+=+5\" or \"x-1+=+-5\"
\n" ); document.write( "\"x+=+6\" or \"x+=+-4\"

\n" ); document.write( "The roots are 6 and -4.

\n" ); document.write( "y-intercept: set x=0 and evaluate.

\n" ); document.write( "\"y+=+2%280-1%29%5E2-50\"
\n" ); document.write( "\"y+=+2-50+=+-48\"

\n" ); document.write( "The y-intercept is -48, or (0,-48).

\n" ); document.write( "3) roots -3 and 7; coefficient a is -1/5

\n" ); document.write( "This one is nearly done for you:

\n" ); document.write( "\"y+=+%28-1%2F5%29%28x%2B3%29%28x-7%29\"

\n" ); document.write( "maximum value: by the symmetry of a parabola, the maximum value is at the x value halfway between the roots, at x=2.

\n" ); document.write( "\"y+=+%28-1%2F5%29%282%2B3%29%282-7%29+=+%28-1%29%28-5%29+=+5\"

\n" ); document.write( "The maximum value is 5.
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