Answer:
d .
x=11
Step-by-step explanation:
ML and JK are chords of the circle
MN*LN=JN*KN
(x-7)*(x+21)=(x+5)*(x-3)
x^2+21x-7x-7*21=x^2-3x+5x-5*3
x^2+14x-147=x^2+2x-15
x^2-x^2+14x-2x=147-15
12x=132
x=132/12=11
