<PRE><B>Question 322477</B>
Using the principle of zero; you set both solutions of x to equal zero and work backwards. 
x=9     x=16
x-9=0   x-16=0

Now apply FOIL to calculate the equation from these two binomials

(x-9)(x-16)=0

First    x*x=x^2
Outer    x*-16=-16x
Inner    -9*x= -9x
Last     -9*-16=144

Combine the like terms of -16x and -9x to equal -25x

Therefore, the original equation is x^2-25x+144
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