Check the picture below.
keeping in mind that the point of tangency for a radius line and a tangent is alway a right-angle, since the "red" chord is parallel to the "green" tangent line outside, then the chord is cutting the "green" radius there in two equal halves at a right-angle, as you see in the picture.
we know the chord is 10 units long, so 5 + 5, since is perpendicularity with the radius will also cut the chord in two equal halves.
anyhow, all that said, we end up with triangle you see on the right-hand-side, and then we can just use the pythagorean theorem.

Answer:
Question 1: -2xy + 7x
Question 2: 8t - 4v and -4v + 8t
Question 3: -e + 10k and 10k -e
Question 4: x = -3
12^2 +b^2 = 20^2 because of the Pythagorean theorem
144 + b^2 =400
B^2 =256
B=16
Answer:
8×10^21
Step-by-step explanation: