Question 1209225
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x = page number on the left
x+1 = page number on the right
x*(x+1) = product of those numbers
x*(x+1) = 756 is one possible starting equation


Do a bit of algebra to convert it to x^2+x-756 = 0.
Compare that to ax^2+bx+c = 0 to find a = 1, b = 1, c = -756


Those items are then plugged into the quadratic formula {{{x = (-b+-sqrt(b^2-4ac))/(2a)}}}
I'll let the student handle the scratch work. 
The solutions are x = -28 and x = 27.


Ignore the negative value. A negative page number isn't allowed.
x = 27 leads to x+1 = 27+1 = 28.
The two pages are 27 and 28
27*28 = 756
27+28 = <font color=red>55</font> is the final answer.
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