Question 36155
(x+7)(squared)+(x squared)= (x+8)(squared)
2x^2+14x+49= x^2+16x+64
x^2-2x-15=0 
Factor to get:
(x-5)(x+3)=0
x=5 or x=-3
X cannot be negative so x=5 is the only solution.
Cheers,
Stan H.