Question 24466
sqrt (x-7) - sqrt x = -1 
 1- sqrt x = sqrt (x-7) 

SQUARE BOTH SIDES
1+X-2(X)^0.5=X-7
1+7=X-X+2(X)^0.5=2(X)^0.5
8=2(X)^0.5
8/2=4=X^0.5
X=4*4=16