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What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

Will give let f(x)=2x and g(x)=[tex]2^{x}[/tex] graph the functions on the same coordinate plane. what are the solutions to the equation f(x)=g(x) ? enter your answers in the boxes x=[? ] or x=[? ]

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2