Formula distance between two points=√((x2 - x1)2 + (y2 - y1)2)
Now distance between (x,7) and (1,15) is 10
√((x-1)2 + (-)2) = 10
(x-1)2+(-)=102
(x-1)2=100-
(x-1)=√
x-1=±
x-1= or x-1= -
x=+1 or x=-+1
x= or x=-