Question 597446
sqrt(z+5)= 2z
z+5=4z^2 square each side.
4z^2-z-5=0
4*-5=-20. the factors of -20 whose sum is -1 are -5 and 4
4z^2+4z-5z-5=0
4z(z+1)-5(z+1)=0
(4z-5)(z+1)=0
4z=5
z=5/4 This is the only answer. 
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Ed