Answer:
x = 11
Step-by-step explanation:
The measure of the angle formed outside a circle when two secants intercepts = ½(the difference of the intercepted arcs)
Therefore:
5x - 10 = ½(13x + 7 - 60)
Multiply both sides by 2
2(5x - 10) = 13x + 7 - 60
10x - 20 = 13x - 53
Collect like terms
10x - 13x = 20 - 53
-3x = -33
Divide both sides by -3
-3x/-3 = -33/-3
x = 11