Question 44975
find the possible values of a if the points with the given coodinates are the indicated distance apart 
(4,7), (a,3); d = 5 

distance = sqrt[(4-a)^2+(7-3)^2]
5^2=16-8a+a^2+16

0=7-8a+a^2
(a-7)(a-1)=0
a=7 or a=1

Cheers,
Stan H.