Answer:
x = 8
Explanation:
In a circle if two chord intersects as shown in figure
and length of a chord at point of intersection is a and b
and length of another chord at point of intersection is c and b
a*b = c*d
using this relation here, we have
8*(x+7) = 10 * (4 +x)
=> 8x + 56 = 40 + 10x
subtracting 40 and 8x from both sides
=>8x + 56 - 8x -40= 40 + 10x -8x -40
=> 16 = 2x
=> x = 16/2 = 8
Thus, x = 8