document.write( "Question 622852: What is the equation of the quadratic function with roots 0 and 2 and a vertex at (1,5) \n" ); document.write( "
Algebra.Com's Answer #391696 by math-vortex(648)\"\" \"About 
You can put this solution on YOUR website!
Hi, there -
\n" ); document.write( ".
\n" ); document.write( "One way to solve this problem is to write the equation in vertex form:
\n" ); document.write( ".
\n" ); document.write( "\"y=a%28x-h%29%5E2%2Bk\"
\n" ); document.write( ".
\n" ); document.write( "When a quadratic is in this form, the point (h,k) is the vertex of the parabola. We know that the vertex of the parabola is (h,k)=(1,5).
\n" ); document.write( ".
\n" ); document.write( "Substitute those known values for h and k in the equation.
\n" ); document.write( ".
\n" ); document.write( "\"y=a%28x-1%29%5E2%2B5\"
\n" ); document.write( ".
\n" ); document.write( "We know that two roots of the quadratic are 0 and 2. Roots of a quadratic are points where the graph crosses the x-axis. Thus the points (0,0) and (2,0) are on the parabola.
\n" ); document.write( ".
\n" ); document.write( "We can substitute one of these points for x and y in our equation. Then we can solve for a. Arbitrarily, I'll choose the point (0,0). Either point will work.
\n" ); document.write( ".
\n" ); document.write( "\"y=a%28x-1%29%5E2%2B5\"
\n" ); document.write( "\"0=a%280-1%29%5E2%2B5\"
\n" ); document.write( ".
\n" ); document.write( "Simplify and solve for a.
\n" ); document.write( ".
\n" ); document.write( "\"0=a%28-1%29%5E2%2B5\"
\n" ); document.write( "\"0=a%2B5\"
\n" ); document.write( "\"a=-5\"
\n" ); document.write( ".
\n" ); document.write( "The equation for this quadratic is
\n" ); document.write( ".
\n" ); document.write( "\"y=-5%28x-1%29%5E2%2B5\"
\n" ); document.write( ".
\n" ); document.write( "Feel free to email me if you have questions about this solution.
\n" ); document.write( ".
\n" ); document.write( "Ms.Figgy
\n" ); document.write( "math.in.the.vortex@gmail.com
\n" ); document.write( "
\n" );