document.write( "Question 182249This question is from textbook algebra and trigonometry
\n" ); document.write( ": The sum of two numbers is 20. If one number is x, then the other number is ____. Their product is p(x)= _____. Find the maximum value of p. Write a quadratic function to solve. \n" ); document.write( "
Algebra.Com's Answer #136866 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
The sum of two numbers is 20. If one number is x, then the other number is ____.
\n" ); document.write( "It's quite obvious the other number = (20-x)
\n" ); document.write( ";
\n" ); document.write( " Their product is p(x)= _____.
\n" ); document.write( "p(x) = x(20-x)
\n" ); document.write( "p(x) = -x^2 + 20x
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( " Find the maximum value of p.
\n" ); document.write( "Find the axis of symmetry using the formula x = -b/(2a)
\n" ); document.write( "x = \"%28-20%29%2F%282%2A-1%29\"
\n" ); document.write( "x = \"%28-20%29%2F%28-2%29\"
\n" ); document.write( "x = +10
\n" ); document.write( ":
\n" ); document.write( "Find max p(x), substitute 10 for x in the equation
\n" ); document.write( "p(x) = -(10^2) + 20(10)
\n" ); document.write( "p(x) = -100 + 200
\n" ); document.write( "p(x) = +100
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Write a quadratic function to solve.
\n" ); document.write( "-x^2 + 20x = 0
\n" ); document.write( "Factor out -x
\n" ); document.write( "-x(x - 20) = 0
\n" ); document.write( "therefore:
\n" ); document.write( "x = 0
\n" ); document.write( "and
\n" ); document.write( "x = +20 \n" ); document.write( "
\n" );